Bringing back the World Warriors was the best thing for 4. If they release an SF without Vega or Makoto, there’s a strong possibility I just wouldn’t even bother with it.
New characters are great. I think 4’s are pretty underwhelming over all, though, for a handful of reasons. Abel, for instance, is bland as fuck. He plays alright, and thinking about it I should find his gameplay exciting and appealing but I simply don’t because he fails to keep my interest with his appearance, voice, story or basically any other facet of his design. Was it all a dream? I wish.
Compare that to Viper. She’s exciting, effective and modern. Quick mixups, feints, multitudes of options keep pilots interested. Flashy play and good character design keep spectators. Some
Seth, Fuerte, Gouken, even Juri all have their own problems. Seth is, again, completely generic. People want him to be Urien, or to play more like a “Street Fighter”, or this or that and in the end he’s a tall naked pile that doesn’t satisfy anyone. Or nearly anyone, anyway.
Gouken too, somewhat, and he may alienate those who would like him because he seems so much like a shoto on the outside but doesn’t play like one.
Juri, from my own experiences, appeals mostly to more casual players. I’ve seen a few dozen people pick her up, but they tend to be people who don’t stick with the game. Contrasting that, a good friend of mine mains her. So I’m not saying she ONLY appeals to casual players, but I can’t answer why she’s not played more often. Not good enough? Don’t like zoning /fireball storing? Too hard?
But, every one of these characters, despite my personal gripes or distaste for them, has plenty of loyal fans. I think Rufus is a turd, but people still play him due to his competitive viability. I don’t care for Hakan, but I know more than a few fanatics.
Point being, even if some of us were underwhelmed by the new additions I think they’re doing relatively fine. Throwing away the old favorites would be awful.
Keep adding new characters, keep the adored ones, drop the hated ones or closet them to adjust and bring back later.
That seems the best way to go to me.