i also theorize that all the campaigns that werent leon's were meant to be DLC originally. but given how the world caught capcom constantly ripping off the consumers by hiding content on the disk, they realized that they would never get away with it. (operation raccoon city, asuras wrath, street fighter vs tekken)
there is alot about this game that feels incomplete and rushed.
this would explain why all 4 campaigns feels so incongruent.
I think companies really should take more time with thier games instead of trying to get them onto shelves as soon as possible, Take Smash Bros 4 on the Wii U, it was announced at the start of 2012 and its only schedualed for a late 2014 release, thats why games like Smash Bros never need updates because they are already perfect, just wish Capcom would take some lessons from other patient companies.