When Flores wasn't re-signed, I was thinking the same reason. Brian has gone on to show he deserves respect in the NFL and can run any defensive show. He is also strong enough to stand up against Coach Tomlin but the situation reminded me a lot of Dick L. when he left.
I wanted Flores to stay and inside hoped he would be Coach Tomlins replacement.
It's too bad because we had him right there to take over. Flores seems to be recognized as the best DC in the NFL right now and maybe the only defensive guy who's considered to be an innovator. I also think his style of coaching is something this team needs right now.