He'll gut the team and start over from scratch, willy nilly hiring a bunch of his own cronies to run the Bills which will backfire end in disappointment and promises of a rebuild with a new GM.
Seriously tho, I wonder if he's tight with Bill Cowher, being a Pennsylvania guy. I'm sure he's got some of his own guys he'd like to bring in. Hopefully he learned from the Sabres experience that you can't build a championship team overnight by over paying for a few high priced FA's.
When he took over the Sabres, the gave the existing regime (even after a year of failure) another chance to turn the thing around and prove themselves. He was patient with them but ultimately the writing was on the wall. With the Bills on the upswing, I would think he gives the GM and head coach at least this season and next to take this team to the playoffs and then go from there. He won't fire anybody just to bring in his own guys, he'll give these guys a chance before making any moves.