One thing to point out. I beilieve the other two parts of the triology wont be labeled as "Expansions" but as total stand alone games.
Im playing the campaign on Hard and its fucking difficult. Still havent finished it yet.
Oh and the campaign is not short if you play it on hard... not to talk about brutal. Seriously its fucking hard guys. Whoever completed it on normal and then went on with his complaining rampage on various forums saying that its too short should just stay quiet.