Cavani is far better than all of those but Messi and probably Henry but not necessarily at that point in Henry's career (Balotelli could be of similar quality but he was much, much younger when they played together). He's leagues better than Lavezzi. The other issue is that he didn't stay at nearly any of those places -- that's no coincidence. He doesnt' like sharing the goalscoring opportunities.
He went to Juve and left when Calciopoli hit. He went to Inter after and stayed even after Mancini buggered off but Barcelona came with a ridiculous offer and Inter bit their hand off. It didn't work out in Spain and Pep wanted to move him on, so he went to Milan - who then went through their own mini-crisis and got rid of all their big earners in 2 years. So now he's at PSG.
Arguably the only club you could say he left purely for his career's sake is Ajax, everywhere else had other circumstances surrounding his position. I'm not saying Ibrahimovic is a paragon of stability, just that I don't see why Cavani signing means he's gone.