The worst parts about SFIV are
>Acquire Ultras for getting your ass beat
>No throw invulnerability after hit/block/wakeup/air reset
>Vortex hell
>Option select hell

I also hate that every game after it used its combo structure. I'm tired of the whole "link buttons into buttons into other buttons into juggle into ultra/super" for every character. Same goes for every character having big combos starting from jab/crouching shorts.