I’ve said it before but I’d legit be hyped for characters like Venom, Predator, Raphael, The Undertaker, and All-Might. Not saying that it’s at all likely or even a good idea but there’s definitely a ton of characters not originating from video games I’d love to play in Smash. Characters like Shrek and SpongeBob less so because I’ve never been personally invested in them. Either way, I don’t really expect any of that to happen as the games currently stand so I’m more that happy to stick to gaming specific characters.
That's perfectly valid too.
I mean, while I don't share the sentiment, I do still understand it. Like, I'd be super down for a Marvel platfighter or a new Jump Stars or completely new manga/anime crossover platfighter, but I like there to be some kind of focus and fixed scope when it comes to crossovers. All crossovers stem from "thing I enjoy interacting with other thing I enjoy," but if too many things crossover it kind of has the opposite effect in some respects.
Adding more options for crossing over winds up limiting who can be added from each individual series/IP. Something has to give and if adding your Goku's and Marvel heroes and whatnot means characters like Isaac or secondary Zelda characters or really deep cut/creative picks in the vein of
are swept off the table and into the bin for good then I'd rather that scope not expand.
It's been said plenty before, but there's so much to pull from within Nintendo's catalogue alone. That said, we've also had third parties onboard since Brawl now. People like to push the whole "celebration of gaming" comment and say that Smash is lacking in several areas, but Smash will always be lacking because the scope is so large now. Even a dedicated Smash vs one third party, would have plenty of possibilities to fill several rosters.
For me at least, it's not that non-gaming franchises lack any characters who I'd find appealing in a platfighter, I'd just prefer them in their own projects with manageable limits/expectations.
I'd rather keep Goku out of Smash, but I'd absolutely love a DBZ or manga crossover platfighter. I know it's not the same as Smash is Smash and one of the big reasons is that people want "x" character is to interact within Smash specifically, but I personally feel it'd be kind of unsatisfying at that point due to how limited the content per franchise has to be.