I hope not, I have never rated Ibrahimovic. I have never seen him do anything of significance on the big stage whether for Sweden or in the Champions League. Ibrahimovic looks good in Italy when he has time on the ball and everyone gives him space to play with the ball at his feet, but he won't get that time and space in England and i don't he will succeed in the premier.
I can't see United given up on Berbatov yet, he offers a different dimension to what they have and would expect him to be given another year at least. The only major change I can see at United is if Tevez as expected leaves and than United will need to bring in another striker to replace him. If you replace Berbatov with Ibrahimovic, than United will have to work in two new strikers, and that's tough to do.