I never completed my Avengers line, I only got Loki, Iron Man VI and VIIBD, and Thor. I was going to go back but then they announced Avengers 2, now I don't see the point. I may still get 1 or 2 figures, like Widow and Fury, the chances are the AOU figures will be better.
So I would wait and see if the figures are better than your current ones(if your worried about duplicates) and then sell the ones you have. I will say though, because I never got the complete A1 line, I will definitely be getting everything from this movie