bar any injuries, I think Milan could relatively comfortably make it thru, especially if there is some fresh blood in midfield coming too. As for Arsenal, I just don't think they are as strong as in 2008 and Milan is not as weak and fed up either ... and more disciplined tactically too. Should RvP get injured, which isn't a far-fetched scenario by any means, the Gunners are as good as dead, imo.
this being said, anything can happen in a game - a RC here, a PK there. And, as I mentioned there is a lot of time till the games, lot's of things can happen till then.
Should be an entertaining encounter, that's for sure