Riverdale and Nancy Drew are both CW shows, with the latter being a newcomer to the popular network. Both feature plenty of elements deriving from mysteries to solve and feature ensemble casts consisting of (primarily) teenaged characters.
A crossover wouldn't be totally out of the question; while they have their differences, both shows have certain key points in common. However, even though they share similar characteristics, and appear on the same network, should they appear onscreen together?
Awesome: Relatability
Both Riverdale and Nancy Drew have dilemmas of similar nature. Romance, friendships, dark secrets and the like are elements that are no stranger to both shows. It would create a certain even flow in a crossover, and it would make it easier for the characters from both shows to relate to one another, and to not freak out at whatever complex situation (dark secrets or otherwise) that follows either one or both casts in the crossover. Plus, they could commiserate over the problems that arise in their respective hometowns.
Not Awesome: Age Differences
Okay, granted, the characters on both shows aren't too far apart in age. However, the age difference that does exist is a big deal because it puts both casts of characters in different places in their lives. Nancy and her gang are graduated from high school, doing their own things out in the "real world", so to speak. Archie, Jughead, Betty and the others are still in high school, wondering what comes next and just trying to get through school in one piece. This could cause problems in the sense that Nancy and her friends may consider themselves a bit wiser for their experiences as young adults, and Archie and the others may feel like they're being condescending, for instance.
Awesome: Supernatural Crossover
Nancy Drew is on a level all its own with its supernatural characteristics. Ghosts are certainly prominent, and the gang has hosted séances before. They've all seen some pretty disturbing things--things that perhaps even the Riverdale cast would find hard to comprehend.
It would be interesting to watch the reactions of both casts, and to find out how they'd conquer such an obstacle together. Even better would be to find both casts facing a new kind of supernatural element that neither has encountered before.
Not Awesome: Too Much Darkness
Both Riverdale and Nancy Drew have dealt with some disturbing things. Murder, family secrets, betrayals, family dysfunction...the list goes on. They're no strangers to darkness in several different forms. Plus, as Nancy Drew has just one season under its belt thus far and Riverdale has several seasons under its belt, the latter has clearly dealt with more darkness over the years. Riverdale makes Nancy Drew look like an amateur in this case, and it could cause something of a problem between the two shows in a crossover, if say the Riverdale cast considers themselves more experienced or if the Nancy Drew cast is too overwhelmed.
Awesome: Solve Mysteries Together
The casts of the two CW shows coming together would be a perfect match detective-wise. Witnessing Betty, Jughead, Nancy and the others put their mystery-solving skills to use would be worth watching in itself. They each have their own methods, and could catch something someone else missed, or work that much faster with a bigger team. They could tackle several, or more likely one big mystery, in a crossover. Not to mention they could continue that crossover in a part-two episode; for example, half of the mystery can take place in Riverdale, and then the second half's setting could be in Nancy's hometown, Horseshoe Bay. The possibilities are limitless.
Not Awesome: Too Many People, Too Many Conflicts
Obviously, both series have larger casts than most shows. It's hard enough to find a balance with their own casts, ensuring everyone gets a certain storyline and that it's followed through. Finding a balance between the two casts would certainly pose a challenge. Plus, each individual has their own baggage and conflicts that they carry.
Ensuring all these things are addressed, or dealt with (depending on the crossover's storyline) would not be simple. It may just come down to the fact that there are too many characters to follow, and by extension, it would make it hard for the audience to follow them and the overall storyline.
Awesome: Great Opportunity
Sometimes shows need brand-new storylines to once again gain the audience's interests. A crossover could happen in the beginning or end of a season, but a crossover like this may be best suited for mid-season. It could even serve as a mid-season finale for both shows. The crossover would be a perfect way to introduce new characters to both shows, in addition to new storylines, and those factors could be carried into future episodes, or somehow contribute to the end of the seasons for both shows. Again, the sky is the limit, and it could really boost the series' ratings, introducing new audiences to both shows.
Not Awesome: Leadership Problems
Riverdale and Nancy Drew have their own leaders. They have their own teams, and everyone contributes their own thing. It's just how it works. Messing with that dynamic would probably cause some amount of friction between the two casts. No doubt there would be a power struggle, or a demand to do things a certain way. If the casts are too busy clashing, or dealing with the fallout from the clashes of certain members of their respective groups, there's not really much of a chance for them to solve mysteries or anything else, and the crossover would be moot.
Awesome: The Chemistry
On the other hand, despite potential leadership clashes, it would be fun to see the two casts interact. After all, it's never known who will click with whom, and whose chemistry will be palpable. Wouldn't it be fun to see Jughead and Ace getting along? Or to see if Nancy and Betty would become best friends?
The two casts interacting with one another could certainly create some humorous moments and serious moments, and they'd undoubtedly create memorable moments that audiences would no doubt honor with memes and gifs.
Not Awesome: They Already Have Their Own Formulas
Nancy Drew and Riverdale are already operating on formulas that work for them, that have made them the shows that they are. Riverdale has been around for years, and has a loyal and devoted fanbase. Nancy Drew has done well, coming into its own, and has a second season on the way. Riverdale may be too far along to try anything too crazy, and Nancy Drew may still be too new to try anything too radical in turn. Perhaps one day these two shows will unite, but now may not be the best time. After all, both shows march to the beat of their own drums.