The common stereotype of the Marvel Cinematic Universe productions is that they aren't so much adaptations as over-literal translations - that the studio is engaged less in finding interesting new things to make from pre-existing properties than simply putting whatever already worked on the page directly up onscreen and jettisoning any troublesome creative whose "vision" doesn't cotton to that (see: Wright, Edgar.) Not helping matters is that it's a stereotype that a good deal of the mega-franchise's fanbase is all too eager to agree with: Yes, they'll say, Marvel puts the characters up onscreen looking like themselves (well, except Scarlet Witch looking like a forgettable nemesis from Charmed, but that was always going to be a lose-lose) rather than just handing out black pleather onesies and calling it a day like the X-Men movies. Yes, they've preserved (and enshrined as a new industry-standard) the ideal of a sprawling story-to-story continuity, even where it kneecaps the ability to tell stories of other kinds.
The problem with this (both as criticism as and as praise) is that it shortchanges what the studio has actually been good at. Yes, it's true that Marvel tends to have more faith in the idea that these properties were already good enough to be worth filming to begin with, but they've proven equally adept at finding which new angles born of the films' circumstances work well and putting them to good use: Did they necessarily intend for Loki (of all characters) to become a major brand ambassador? Probably not, but they've leaned into fandom's fixation on Tom Hiddleston almost as happily as he has. Clark Gregg's Agent Coulson was popular enough with audiences that he got a resurrection, his own TV show and a retroactive insertion into the comics' continuity. People like Idris Elba? Give Heimdall more to do - even though the main thrust of his character is that he does exactly one thing better than anyone else is able to. They've made only one huge misstep thus far: underestimating audiences' fondness for Scarlet Johansson's Black Widow.
Agent Carter's first season, was quite possibly the purest distillation of that other side to Marvel's successful formula. While technically based on a supporting character from the Captain America comics (the original WWII era ones,) Peggy Carter is otherwise as conjured wholecloth from the film division as Phil Coulson; she exists as a fixture in the pop-culture imagination almost solely on the basis of Hayley Atwell's considerable charisma and the quirk of fate that unlike other fan-favorite supporting players (Pepper Potts, Ant-Man's extended family), she couldn't simply be carried over into Captain America's future outings - meaning that Marvel would have to make something special just for her in order to make use of the asset. Giving her a TV show? It was the most sensible call the studio could've made.
But sensible or not, the actual pitch for Agent Carter was something else: A period spy procedural, set adjacent to the goings-on of the MCU superhero scene but also grounded in the late 1940s and framed as an allegory for the postwar devaluing of female contributions? Even today it simultaneously feels like something Marvel was the last studio you would have expected to take it on, yet also the only studio capable of making it work. And while not perfect by any means, that first season was something to behold - pushing that central proto-feminist allegory with a fervor that only seems subtle in the wake of Jessica Jones, making full yet unintrusive use of the Marvel canon (Dr. Faustus, Jarvis, The Howling Commandos, a prototype Black Widow), and gifting audiences with a heroine unlike any other on the airwaves.
There were issues, certainly; especially on the budget side in the finale. but when Agent Carter was working it was positively on fire. What it did the most right was stay fixed on the strength of its central conceit of Carter's situation (a war hero, chafing at being pushed into menial work after returning to civilian life, conducting missions of her own outside the supervision of her arrogant colleagues) as a stand-in for the general plight of other woman at that actual point in history. Encouraged to take up non-traditional roles on the homefront to support the war effort ("Rosie the Riveter," etc) American women of the 1940s would see those roles swiftly pulled away and were told to fall back in line when the men returned from war (the unwillingness by many to do so was the spark that would ignite the modern feminist movement in the coming decades).
Peggy Carter faced a more literal version of this, with her wartime heroism being deliberately obscured and her undermining of male authority figures being more about thwarting a terrorist act; yet the allegory allowed for an intriguing tour of "lost era" history in terms of sexual politics (Peggy hides out at a women's-only hotel that offers welcome protection for single women - but only if they stay "virtuous") and gave the MCU another great villain in Bridget Reagan's unhinged Soviet assassin Dottie Underhill, a.k.a. the pre-Black Widow Black Widow. It also knew how to milk a great ensemble cast, even while being explicitly a star vehicle for Atwell.
So it was sort of discouraging to realize, midway through Season 2, that it just wasn't working. Not in the sense that Season 2 is bad television - it's really not, especially considering what usually passes for programming meant to "fill in" during another series midseason break - but it was a definite come-down after how unique and interesting Season 1 ended up being. Maybe that's mainly the expected effect of getting a good show that you have no idea what to expect from versus a follow-up season where expectations are all you have, but it was consistently disappointing (not everyone agrees, obviously) to continue tuning in to Agent Carter: Season 2 and being left mainly with a feeling of "that's it?" Now, having come to the end of the season, it feels very much like a decent effort but largely a missed opportunity - though not one that can't be recovered from.
The season started promisingly enough, with a relocation to 1950s Los Angeles and the promise of a shift to "dark side of Hollywood" detective intrigue, but the narrative seemed to quickly come off the rails as it strained in multiple directions at once, each less interesting than the last. It was about a mysterious contagion, "Zero Matter," spilling into our world from a dimensional rift opened by atomic testing. Then it was about a secret council manipulating the world economy (implicitly some variation on The Illuminati but likely just another subset of HYDRA.) Then it was about unscrupulous FBI enforcers muscling in on the SSR's territory under the guise of a Communist witch hunt. Then it was about a Zero Matter infected actress/science-genius (got to admit, "Evil Hedy Lamarr" was not a villain I would've been expecting) trying to re-open the rift. Then it was about... something to do with Jarvis' insecurities, I think?
It's not that the pieces weren't there: The returning characters (Carter, fellow Agents Sousa and Thompson, Jarvis, Howard Stark, etc) all acquit themselves well, while newcomers like Reggie Austin's Jason Wilkes and Wynn Everett as the aforementioned actress Whitney Frost were welcome additions to the ensemble. The basic idea of Carter's signature blend of action, deadpan comedy and soapy character melodrama dropped into noir-era L.A. was nothing if not promising. But the stakes didn't feel as high as they should, and the themes didn't feel as weighty as they should. Nothing seemed to matter as much.
Fight scenes would break out and, while they were as well-staged as before, the visceral immediacy (i.e. "I know what these people are fighting about and I am invested in the outcome") that came with Season 1's brawls was missing here; replaced with "Oh, I guess it's time for more punching now." Story beats that should've felt important (atomic weapons! The Red Scare! 50s racism!) felt perfunctory instead - less "Here's a point we're making about this," and more "We're mentioning this because it's the 50s and you expect it to come up." Season 1 may have only had one big idea to get across i.e. "post-WWII America was uniquely rough for working women," but it got it across organically as a natural part of the story that informed the characters decisions and defined their world.
What had gone awry with Season 2 didn't fully crystallize in full, though (for this author, anyway) until the penultimate episode, "A Little Song, A Little Dance." Specifically, the Hollywood Musical dream sequence that opened the episode. The sequence itself is fine, reinvigorating the sense of inventiveness and tone/location shifts that helped keep Season 1 so consistently fresh; but it announces itself upfront as a summation of Carter's psyche and the overall theme of the story and then proceeds to make that central subject... whether or not Carter is going to choose between her feelings for Wilkes or Sousa. Again, cute routine, but... that's it? Within two seasons we've gone from Peggy Carter: Superhero standard-bearer for the plight of an entire generation of women as an overarching theme to Peggy Carter: Which guy will it be? In the end, Season 2 just couldn't find something to be about - and that's a problem for a franchise where being "about something" was most of the original point.
There were bright spots, to be sure, but most of them were just that: Spots, bright on their own, not brightening any of the broader production. Reggie Austin was compelling as Wilkes, especially when saddled with the difficult "I'm the only black person on a period show so guess what my subplot keeps coming back to" baggage, but his character didn't add much beyond the trite romantic complication and a chance for the show to establish that despite the era none of the main good guys were even a little bit racist. Whitney Frost (whom we're supposed to take as beginning her journey to become Marvel villainess Madame Masque, though she doesn't suit up) is interesting, but it's disappointing that she's presented as another "evil version" of Peggy ("evil rebel against sexist-underestimations," as opposed to Dottie's "evil tomboy" angle) instead of developing her as a singular entity. "Zero Matter" apparently being a sliver of world-building for Doctor Strange is a nice detail, but not one that feels terribly important.
Fortunately, none of this falls under the heading of "unfixable" should Marvel and ABC decide to try for a third season. Finding a more interesting theme than whether or not the lead character can choose a love interest should be too difficult for a half-decent writer (you can see the logic in doing it for Season 2 in terms of taking Peggy from a symbolic to emotional arc, it just didn't work) and there's plenty more Marvel ephemera to pore through considering we still haven't fully gotten to the "formation of S.H.I.E.L.D." business. The showrunners clearly aren't ruling it out, given that the season ends with a main character shot in the chest by an unknown assailant and Carter now in possession of a Secret Council pin that's actually a key to some unknown lock. Ken Marino as Frost's mobster boyfriend Joseph Manfredi, another of the season's missed opportunities (he shows up and turns out to be a fun/interesting character just as everything is ready to wind down) is still at large and could be a gateway character for the ever-enjoyable presence of The Maggia, a.k.a. the Marvel Universe version of The Mafia.
The bigger question will be whether or not the series is asked to come back - or wants to. While its generally assumed that Agents of S.H.I.E.L.D. is in no real danger of cancellation despite generally average ratings because Disney/Marvel (likely) want it to garner enough episodes for a syndication package, that same long view doesn't likely apply to 10-episode midseason special series. In addition, Atwell has already set up another series with the network, and while they were quick to confirm that she'd be afforded room to do another run of Agent Carter, whether or not she wants that level of a workload is another story. As is, Season 2's startling lack of direction or purpose compared with Season 1 feels an awful lot like what happens when a nifty individual idea ("Let's show them what happened to Peggy between Captain America: The First Avenger and the present!") gets popular enough that you're compelled to make another one, even if you don't necessarily have a strong idea for it. It's entirely possible that Agent Carter was simply not meant to be an open-ended thing.
Maybe that's for the best. If Agent Carter can only come back to diminishing returns, it may be better that Marvel/Disney find something else to fill Agents of S.H.I.E.L.D.'s midseason slot. That doesn't have to be the end of Peggy Carter, either: One-off TV movies would feel like a natural progression, or maybe a swing back to theaters - there's no rule that says all of the Marvel Cinematic Universe movies are required to take place in the present, after all, and while a mildly popular TV event series may not be enough to launch a blockbuster franchise of its own, there's also no rule that says Carter couldn't be a featured player in some other past-set adventure (she appeared in flashbacks for Ant-Man, which also established that there were active superheroes operating in the MCU in the years between First Avenger and Iron Man, for one thing). The publisher's B and C-list bullpens are positively lousy with characters who don't make a lot of sense outside their 60s, 70s or 80s origins, so why not keep them there?
The bottom line is, Agent Carter: Season 2 might have been a letdown, but Agent Carter is still very much one of Marvel's better creations - and they'd do well to find material worthy of her.