The Pokémon franchise recently crossed the major milestone in the form of its 25th anniversary, and there seem to be some welcome shake-ups to the games' formula that will hopefully pan out as fans are expecting. Aside from the mainline series expanding with the Diamond and Pearl remakes and coveted Breath of the Wild-like Legends: Arceus that will finally aim to break the mold, spinoffs seem to be becoming more relevant.
Longtime fan-favorite Snap got a sequel to both critical and commercial success, so it could be a nice change of pace if more attention is given to experimental offshoots, and there's plenty of dormant series that should regain a chance to shine. The N64 Stadium/Stadium 2 and GameCube Colosseum have their subsection of fans and could be worthy contenders, so here's why the former deserves a reboot and why the latter makes more sense.
Stadium: The Oldest Of The Two
In terms of technical limitations, Pokémon Stadium and Stadium 2 would clearly benefit the most from a reboot--or any kind of revival. The two games have been untouched in that regard on the Nintendo 64, with the first being 22 years old and the second 20.
Gaming technology has obviously come a long way, so this spin-off series definitely has the most to gain in this department, with modern-day QOL features and new innovations since the last time fans experienced these games. Colosseum could also make use of a technical overhaul from the ground up, but seeing Stadium in a new light on more powerful hardware could be worthwhile in its own right.
Colosseum: Arguably Bigger Following
It can't be denied that Colosseum has arguably garnered a bigger following over the years within the Pokémon fanbase, and it's often looked back fondly as the underrated "classic" for bringing the formula to consoles. For that reason alone, it might be more profitable to look into rebooting the series on modern hardware, if not outright giving it another sequel.
The game surely had its limitations, like a limited creature roster, but gave a good early taste of what a console Pokémon RPG could eventually strive to be. Combining this with it being a more recent entry in the gaming franchise, and it could be an even easier sell than these games typically already are.
Stadium: Successor For The Competitive Meta
The Stadium series are strategy games, doing away with the RPG genre and focusing more on turn-based battles. Mini-games aside, a reboot of these games could have a good reason for filling in as the next official competitive metagame. It would be more centered around teambuilding and strategizing for tournaments--both official and unofficial--than the mainline RPGs are since there's no story to get through first, which would also make competitive play more accessible.
By extension, that could give a benefit to the mainline games in that they can lean more into having a richer single-player experience--particularly in the post-game department. Though, they could still have transfer connectivity with a Stadium reboot to import teams like the originals.
Colosseum: First Proper "RPG" Spinoff
Pokémon Colosseum was the first time the franchise got a spin-off game that retained the traditional JRPG core from the mainline games, so naturally, it holds plenty of love from the community for being a console RPG alone. Fans have finally gotten that with the Nintendo Switch forcing The Pokémon Company and Game Freak to accommodate for console gaming.
Though, in terms of quality, the Switch titles didn't get the level of innovation to gameplay fans might expect after 25 years. But, with Stadium being stripped to largely just the turn-based combat, Colosseum probably makes more sense to reboot since it's a whole story and world to reimagine, making the content potentially more attractive--especially if Legends is received well critically.
Stadium: Potential For Greater Visuals
In terms of what fans have gotten so far, New Pokémon Snap is among the best-looking games in the franchise so far. Given the scope of the game, it's not hard to see why. It's not a particularly expansive game with multiple large-scale worlds, so developers Bandai Namco could invest more heavily into the visuals the game did have.
They delivered in spades, as the different zones felt alive, as did the actual Pokémon. 3D models were well done with vibrant colors and animations that made the game feel like players were traversing through exciting, densely-populated, living ecosystems. Stadium's comparatively smaller scope could allow for something similarly exceptional in graphical and technical fidelity, though, likely not as strong as Snap due to the number of creatures that would be in the former.
Colosseum: Expanded Roster
While Colosseum includes a solid amount of species in-game, it ultimately only lets the player obtain 49 different Pokémon. To top it off, one of those is the legendary Ho-Oh, which players only get after catching/healing the other 48 and grinding out 100 straight wins in the Battle Mountain.
It's a shame the roster was so limited, but a reboot could be a great excuse to bolster that. It definitely wouldn't need anywhere near the ~900 that exist total, as ~200-250 creatures picked from each of the eight regions could work. It'd be plenty of variety for a spinoff, especially if developers pour the other bulk of their efforts in story, performance, visuals, and creative world design.
Stadium: Long-Running Life Cycle
The Nintendo 64 was capable of handling the whole Kanto and Johto generations of Pokémon, which totaled at 251 species with Stadium 2. Should the series get a reboot on the Switch, it could be all that's needed for the remainder of the console's life cycle. This hypothetical spinoff--thanks to modern technology and shedding RPG gameplay elements--could include, say, the first four or five generations (493-649 species) to select from at the start.
The remaining generations could later get patched in and, with whatever Nintendo follows up the Switch with in the next console generation, the game could get remastered with new content. On paper, this could be a game with a long, healthy life cycle.
Colosseum: XD: Gale Of Darkness
Of course, should a straight reboot be done for the GameCube original and get received well, XD: Gale of Darkness could be next in line. The sequel got a more mixed critical reception due to feeling more like a copy-paste job of a good portion of Colosseum. With some retooling, it could be more adventurous and take advantage of what the franchise has managed to improve on since the 2000s.
The mainline games have come to branch into three(?) series, but it'd be great to see a spin-off that's mostly unburdened while also being a JRPG. It would essentially be a way for other developers to have their own spin on the mainline formula.
Stadium: Revival Of Forgotten Features
Main series games have unfortunately lost some fan-favorite features over the years for the sake of further simplification, but the premise of the Stadium games could be a roundabout way for them to return. This would definitely be more of a consolation prize, but the likes of the Battle Frontier could be one of the features alongside the Gym Leader Castle, but achievable in the postgame.
The games were mostly about strategizing with different teams to run gauntlet tournaments with increasing difficulty, and that's what the Frontier was about to in the Game Boy and DS games. It wouldn't need to stop there, as the World Tournament from Unova could be a viable mechanic, too.
Colosseum: Stadium Would Be More Redundant
As great and nostalgic as it would be if TPC were to reboot/remake/sequel to Stadium on the Switch, the argument could be made for it to be a now redundant game to revive today. Among the major appeals to those games then was that those heavily pixelated monsters that players fell in love with could be in 3D to battle.
But, obviously, the franchise has already gone that route across main games and spinoffs. For some, that appeal could mostly be achieved from playing any of the Switch--and even 3DS--games, making these redundant.