How would the game look like without freeze frames? Some mechanics would certainly look more interesting, making certain movements possible (like extended instant tech, or doing quick iceball ultras) or tweaking the difficulty of other movements (e.g. bumper cancels are easier if you demo+,dash at the same time, but there's less window to perform other needed inputs like dash redirects).
It would probably be interesting in expert+ maps! Unfortunately I don't think I'm going to release this mod, but here is the idea.