Personally, I honestly wouldn't mind future Smash games purely focusing on Nintendo history, even if that means we have to lose out on certain third party picks. Whilst I've always found it cool that crazy characters like Cloud, Joker and Steve got in, I feel like a lot of genuinely reasonable picks have kinda been shot down because of it - for instance, more obscure retro picks like Mach Rider, Sukapon and Takamaru, for instance, are at this point more of a pipe dream than characters like Dante and Scorpion.
I don't have a problem with it, so much as I think Smash needs to focus less on the pure big reveal aspect, and more on Nintendo - after all, characters like Byleth and Min Min could have been received way better if the timing had been better.
The argument of "you don't want third parties!" isn't true either - I just think third parties should focus more on Nintendo history, like Mega Man, Sonic, Pac-Man to an extent, and so on.