This is what I think:
In the next game, they shouldn't try to add any more "new" styles. Let's just take a look at 2 unique styles that were added to sc5:
Zwei and Viola. Viola is arguably broken, and Zwei is arguably the worst character in the game. This is why they shouldn't try to add more styles in the next game, because their just gonna do a shitty job of designing the move sets anyway.
Instead, they should just focus on the styles that they have put the most work into over the years, specifically the ones that keep returning. They can also bring back old styles (zas, Yun, Mina) that appeared in at least 2 games. I imagine it's much easier to balance an already existing move set rather than come up with a brand new one from scratch. Not only is it easier but I think the end result will be characters that are designed more competently and thus more balanced.
They can justify the return of old characters and the removal of new ones from sc5 by making it take place before sc5. Pat is a nice addition and can stay, but seriously, I know many people who would welcome the removal of Viola and Zwei as well. Someone said the less anime the better, well I agree 100%.
Now, about the meter thing;
It's most likely making a return, so you better like it whether you like it or not :) What I would like to see changed though is a general reduction in meter gain, and no more free bar to the losing player. JG should not build meter, the punishment alone is enough reward IMO, it should however retain it's ability to prevent guard crushes, but it should not work on unblockables. Also, there should be a whiff animation for JG, as well as making it FAR less safe if you whiff it. Maybe just have the character flash blue if they whiff the JG. I would also like to see FAR MORE BE's, maybe twice as many per character, and everyone should have an alternate CE (214214 or something) that is completely different from their normal CE.
Also, expect the move sets to reduce even further down to only 50 moves per character. I may not 100% agree with this idea but I'm almost certain it's going to happen. Right now, most characters have 80-100 moves. Yoshi is an exception since he has closer to 180 moves (don't believe me? count them yourself!). But I think 50 is a reasonable target to meet since most people don't use more than that anyway.