I didn't particularly want Amorim when he was at Sporting but that United squad is absolutely NOT built for a back three. No natural wingbacks at all, no good strikers, their best two players are a 10 and a winger, neither of which are a natural fit in his 3-4-3. Terrible fit, but I also think given time he'll do OK once he gets his players.
Our squad on the other hand is a perfect fit for a back three (a real one, not that retarded shit Ange pulled the other day). We have wingbacks and 10's coming out of the wazoo. Amorim would be doing a lot better with our squad than he is at United.