In an ideal world we'd be building a squad based on a system we want to play irrespective of manager. The managers (and players) should then be picked in part based on their ability to play the system and work with the squad in my opinion. But for some reason we still seem to do it ass-backwards, bring in a manager who plays a vastly different system, buy players for it (not very well), bin the manager off, bring in a manager who plays a different system and needs different players like some kafka-esque loop.