Considering when the game was first announced to be 17 years in the future and people weren't even sure how many old characters would be back (if any other than Siegfried and Mitsirugi), I would say it is pretty good that we have ALL of the old main character styles returning in some way except Talim's, Yun's, Zasalamel's, and Rock's. (Plus it is pretty likely some or all could be DLC) We could have gotten all new styles and that is what most people expected when the game was first announced. The fact that instead we got almost the opposite and are only missing 4 of the mainstays (while still gaining a handful of new ones) is pretty good. If the 3 mimic thing is true that is pretty dumb but we still did get most of the old styles plus new ones so I don't exactly feel that bad about it, nor do I think they could have "brought back many" much moreso than they already have.
TL;DR:
We Lose These Styles (Probably...for now)
Rock
Talim
Yun-Seong
Zasalamel
Cassandra
Kilik or Mina (whichever Xiba is not based on)
Amy
We Gain These Styles (at least)
ZWEI
Viola
Patroklos
Aeon (Basically new)
Dampierre (Might as well be new since it is his first competitive game)
Devil Jin
We Keep
All other past styles outside of Guest Characters
Plus, we still technically don't know the movesets for Elysium, Kilik, or Omega Pyrrah...or if there are more CaS only styles...or if there are actually any characters behind the tablet on row 3.
Overall I'd say that is pretty good. However you want to count the new styles as actually new or not, we overall made a profit on number of styles and there are still uncertainties concerning some characters.