For such an experienced manager, 850 games, 'hindsight' is something he shouldn't need and if he does, he should at least learn from it.
Unfortunately Mr. Bruce seems incapable of many things, learning that putting 10 new players into the team and being odds on to lose is but one.
850 games as a manager and still incapable of knowing that having a playing system, is primary logic, just shows that the quicker he is gone the better.
Take Gary Rowett as an example, he has his teams play a system until it is second nature to them and because the squad play the system, it doesn't make it too hard to change team members. Once the squad learn the system he allows for flair to be introduced into the system.
Look what he managed to do with a Birmingham City side that more experienced managers have failed to do.
