It starts with him, yea. I don't think the Bears will part ways with Pace yet but if Trubisky busts (which is all but true now) then they have to roll with a veteran QB and give Nagy a chance to prove he's not part of the problem as well. I honestly do believe Nagy has some underlying issues as well but I wouldn't be opposed to letting him get 1 more season with an acquirable vet (not using draft capital which will be tough to pull anyway)
Pace should be gone just based on his draft misses.