I love 3S, but I am also glad that parry system stayed there. It is what it is, was great within that. I would never say it was perfect though, it has many flaws. Parry itself, and 3S in general. I thought Yun/genei-yin was dumb/unfun to play against. It was more fun for me to play against Chun (with all her issues).
As for what parries did, within the context of that system.
- It killed fireballs in the traditional sense. I just thought of these as just another long poke move (with some extra utility for the EX versions) and something to initiate action/sequences. Plus what Remy and Oro were doing was different with them as well. Plus there was dashes to cover space, which was part of the stew as well.
- It killed the traditional jump-in/anti-air interaction? Probably, but it created something new in it's place. Not better or worse, just different. It was it's own thing and it's mind games within those micro interactions. I liked it. It wasn't like other games, and that was the point I assume. They did take some minor variety layers away when they took away the air-down parry in 3S, but it was fine. Air parries made air to air interaction fun too. Plus adding a decision layer, should I jump and try to anti-air them with an air-air (if they are just jumping into parry what you throw out), instead of staying on the ground. A jump forward/neutral/back button? Anti air ground button into a another move? Do the button, don't do the next move and wait for the parry? Do nothing? wait for their empty jump? it was fun.
3S parries did affect the poke/neutral game (sometimes not for the better) and it did favor some characters move kits more.
Parry in 6 doesn't seem to be the same though, so everybody should be wait and see. I like to hear the concerns too.