So much magical thinking here - in no organisation in any field benefits from making changes without first, carefully identifying the problems asking are they organisational, financial, recruitment, scouting, leadership, managerial, or down to conflicting goals? This is followed, ideally, by establishing within the whole organisation that these are indeed the problems. Then you ask, how can we solve these problems? What do we precisely and concretely need? If at that point the consensus is that the problem is the manager you've triggered another set of questions. What isn't he doing? Can we make changes to help him do it? Only then do you go looking for a new leader. And for heaven's sake, not just by saying he's great, he's available, I like his football style (it might not be replicable in your organisation) or whatever but what is there on his cv to suggest he has the right skill set to solve the slate of problems we've identified.
Otherwise, you're back to doing what this once great club has been doing for a decade; rolling the dice, gambling, winging it, make a hugely expensive and disruptive change without an underlying analysis and strategy and hoping for the best. I wonder how long the new bloke will last? How quickly will the Caf be calling for his head? Who will replace him? More thought, less knee jerk.