So, this is a thing now.
As I'm sure you know, Capcom is kind of notorious for constantly re-releasing their fighting games with some gameplay tweaks and extra characters, it's what they've been doing since Street Fighter II. So now, fourth in the Street Fighter IV series is Ultra Street Fighter IV.
What the trailer promises is 6 new stages (which have been revealed to be ported over from Street Fighter X Tekken), gameplay tweaks, extra modes and features, 5 new characters (Poison, Hugo, Rolento, and Elena ported from SFxT, along with a new 5th fighter), DLC costumes (available for pre-ordering a physical copy), the same deal as with SSFIVAE (physical copy for $40, download for $15), and a release date of early 2014.
Now then, this new mystery fighter. What's been confirmed is that it's not Mega Man or Asura (from Asura's Wrath), they've never been in a fighting game before, and they're "heavily tied to the Street Fighter series." The fans are assuming it'll be a Final Fight character, but I'm not going to assume anything here.
That's all. I'll undoubtedly update my SSFIVAE into this when it's released, and give some more thoughts as stuff is revealed.
HBM , signing out.