"Conker got in smash remix so it would be fine if he got in ultimate!"
ah yes because a smash fangame where the characters are all n64 era graphics, barely have voice acting, and have super simple movesets is exactly the same as a big budget fighting game hyperfocused on making characters as similar as possible to their games, and has lots of aspects of the each game represented.
seriously though isnt the whole appeal of him the fact that he does inappropriate things that cant be replicated in a game like smash? none of what makes him a special character could be replicated. Smash remix could do it well because the animations and moves are simple and the n64 style means his personality can be shown without needing M-rated content.