The way I look at it is this. In my job (not a lawyer), I have to formulate arguments many times that allow for the least amount of questioning possible, unless I am asking for input. Therefore, I try to present positions that allow for the least amount of holes to be poked in them. I know it will never happen, but let's say one of us would get called into Rooney's office and asked our opinion on if Mike Tomlin should stay or go. IMO, you have to keep it as factual as possible.
1. He hasn't won a Super Bowl since 2008.
2. He hasn't been to one since 2010.
3. He hasn't won a playoff game since 2016.
4. He hasn't built his own championship team. (I feel this is a different argument than saying he won with a Cowher team)
5. He hired, and more damning, retained Matt Canada.
6. His penchant for losing a few games each year to inferior teams record wise.
I feel it is very hard to argue with the facts of those things. What could be said in response? But if you go in there saying things like he won with a Cowher team, or he has no coaching tree, or he plays his buddies, or he doesn't discipline right, or he can't be challenged or whatever...holes can be poked into those arguments.