I Saw Phoenix was getting Discussion So I will Chime in
Phoenix is Fine, but I think the TWO Big Probelms with him is that
1. It's not just that he doesn't have enough material, It's also that whatever material he had was used all the Way in UMVC3. You look at all the 3rd party characters that have been in Fighting games like Sonic, Snake, Cloud, Bayonetta, Simon, etc.They might take elements from Their fighting game apperance but they still have unique moves that come from their home franchise. In the case of Ryu, Ken, and Terry, the unique parts about them is how they translate their fighting game Mechanics to Smash
With Phoenix, I really don't see a way how he won't just be a Rehash of UMVC3. Compare him to Dante, who still has 3 Whole games worth of material to use (DMC1, DMC4, DMC5), along with adding in mechanics like Delay based combos, Style meter, the Style System, etc. Phoenix's series doesn't lend well to alot of material. It's why alot of stuff in UMVC3 had to be made up/exaggerated
2. There's another character that's Similiar in function to Phoenix; Professor Layton. Both come from puzzle games that have a Long stored history on Nintendo and Solve mysteries and don't really fight much. The thing is that Professor Layton comes from a Series that has sole more than Ace Attorney, Hasn't been in a Fighting game, so he is more fresh, has more material to supplement a moveset than Phoenix does, and Also has a Top Hat. In terms of Smash fanbase, Phoenix might be more consistent in popularity, but Professor Layton also does have a fanbase in the Smash Community and I believe was especially popular during Smash 4 era.