Milan wouldn't give Arsenal the space no matter what competition it happens to be. Adebayor is top of the charts in scoring in the Premiership, so I don't think we can place attribute the performance to the lack of a strike force. Milan is actually the side without goalscorers up top, something that has hurt them for a while now.
Milan always seem to get the better of English sides. They've been knocking Manure out of the competition for a couple years running, and now it seems like they'll take care of Arsenal at home. A draw is a good result for them considering the circumstances, and they didn't give Dial much around the box and through the center of the pitch.
Milan isn't vastly superior to the top English teams in terms of tactics and defending, but they still are superior IMO. They've been proving that for a while now in the Champions League.