Surely it would place a massive asterisk on all the trophies won during his time at Man City? In future discussions on the greatest manager would this be a talking point which stains our perception on him? Or will he still be lauded as the greatest by some despite the wider context?
There will always be debate as to how influential he actually has been considering each of his managerial roles have been at clubs at the peak of their powers, regardless of how they got there, and by all accounts his input kept them operating at those levels - if not beyond expectations considering he’s won silverware everywhere.
He’ll always be lauded as one of the greatest - any possible club biases or protections had been made and maintained at club level prior to his involvement - yes he aided them getting the plaudits during his time, but I’d argue each of the clubs he’s managed would have achieved similar success regardless of who was in charge, but they would have likely had to have thrown more money to get the job done. Similarly I’d argue he could win silverware regardless of where he managed - providing they had enough to be decently competitive.
He’s coached some of the greatest players of this and last generation, he’s won some of the biggest trophies as a manager for every club he’s coached and is widely respected by fans, clubs, players and media everywhere - in spite of whatever questions about his influence or the clubs political power/corruption.