"tekken & VF are the most balanced games ever!!!" really means "i don't have experience with tekken or VF at a high level"
there's still fucked-up matchups etc., they just happen in a much more subtle way that you can't really notice on video without knowing the game. frame data minutiae and a character's sidestepping ability are things that can create 6/4 or worse matchups, which is a far cry from "Dude throws fireballs and Homeboy has no way to get in". since these kinds of games are so tightly designed, it takes a lot less for something to break that design. having a 12f jab vs. an 8f jab can be the kiss of death, and there's no way non-players would pick up on that sort of thing.
those series also had mechanical changes over the years that old-schoolers rage about, no different from anything else. people who came from the original tekken tag tend to hate bound and the very existence of walls, as they create somewhat MKX-style corner situations. VF5 added 0-frame throws, and i've known of top VF4 players who had meltdowns over that.
finally, although there are nice subtle differences in playstyle, the reality is that 3D fighters have far less variety in the core strategies of the characters. there's much less of a reason to use mid-low tier when they play a lot like the top characters. think of elena in 3rd strike: totally mid-tier, yet you see more Q & hugo in tournament because they have unique stuff while she's just a crappier chun-li. hell, old ken is legit upper-mid in super turbo but gets no love because you might as well play ryu instead. 3D fighters are much more prone to this phenomenon, though i would also put KOF up there in that regard. in a way, i think this makes up for the inherent balance deficiencies of 2D fighters vs. 3D; most 2D games have a lot more lower-tier characters that appeal to someone in a special way. you can see that with all the dedicated low-tier warriors in japan for any fighter that lasts...