I'd agree the replayability level isn't very high, but I wouldn't proclaim it "non-existent" just yet. Though that may just be me, I skipped a lot of side quests and missed a fair few worlds (also I kinda care about my gamerscore, only recently picked up a 360 and feel a bit left behind.)
Still I think theree's enough changes to warrent a second play through... just not for a few months.
