Had Ivan stayed the club and him would have stagnated (admittedly that would have been better than what happened).
He was not the coach he is now, he had to go elsewhere to learn to coach. Remember he was a player coach with very little experience here.
Our attack under Ivan was horrible, second man plays, a team full of back rowers being dropped under and hoping for a crash over in the red zone, and when that failed which it often did, we couldn't construct backline plays to put Manu one on one.
Fortunately for Ivan Manu was a freak you could kick to and he would take on four players and score.