Game legit needs a reboot.
Adding more stuff will just unnecessarily add to the workload, and cost, with diminishing returns in terms of hype. Nothing will top Cloud, Ryu, Megaman, Pac-Man, and Bayo anymore. This roster is as good as it gets.
So it's better to hit the reset button on the roster, do a revamp on movesets across the board, add new mechanics, etc...
You can do 35ish characters, with a lot of new faces, expected and unexpected, as well as some cuts of characters that have become more or less redundant on the roster. Reimagine a lot of the characters that are essentially staples *cough* Ganondorf *cough,* and thus, you've got it set up where people will wanna see returns in future installments, and you've got a chance at trying a lot of new stuff with the game.
Ideally, the game would be made with a more competitive focus (faster engine, etc..), but I'm not crossing my fingers.
But yeah, I have serious doubts the next Smash game would be an upgrade of what's been built thus far. Hell, I have serious doubts that Sakurai will take up the mantle for a 5th time.
Doubles senpai. It's a whole different metagame that 1v1. It's very common for people to pick a ranged character and sit back and spam the projectile. Can it be dealt with? Ofc, but that doesn't make it any less frustrating. It takes the fun away from the game when you gotta deal with a move like that.