You beat me to it!
Not to be picky, but I think it would make the most sense to have the eight "main" fighters from Street Fighter II be the eight Robot Masters. (I'm sure I've thought of this before, even...) Perhaps the Grand Masters could be in Wily's Castle. I just say that because Rolento, Urien, and Rose appear in the trailer...
Besides Mega Man II, the arcade version of Street Fighter II also has an intro with a pan up a big building. Capcom sure likes those.
Now if Street Fighter X Tekken uses the Street Fighter engine, and Tekken X Street Fighter uses the Tekken engine, shouldn't this game be called Mega Man X Street Fighter? Or would the X confuse people (is it pronounced "X" as in the letter X/Mega Man X (not ten!) or "Cross" as it is in the Street Fighter/Tekken cases)?
And wow...overthinking it.
Anyway, whoa, next week for free on the PC? Sweet. I guess I can dust off the NES USB controller I have...