Guile's buffs afaik was an increase in damage and I believe more forward range on his Hard Flash Kick, in addition to hopefully much more useful Ultra. From what I heard with Ryu's Metsu SRK if it's used as an anti air or after an FADC it will do a multihit version like when you fail to connect cleanly with Ken or Gouken's current ones, which theoretically leads to lower damage.
Most of the new ultras for the established characters I can't really see not getting much use, outside of ones that provide a good new level of mixup (Balrog's 360 throw) or in the place of an ultra that was complete ass (Bison, Honda or Claw, maybe Ken's, I heard you can't SRK -> FADC into his new one).
XI Wiki


