Lee was slowly becoming a really good ODI bowler. He was becoming more and more consistant with his line and length and at his pace that is always going to be troubling. He wasn't going for loads, which is the perfect situation, he'll take wickets with the new ball without going at 6+.
It's a shame for you Aussie he got injured, he could have been one of the better bowers of this world cup, despite the fact that pace hasn't suited the wickets, Lee had the versitility to change his game.