As I expect Seattle's offense to continue it's tear, it's a decent bet that Bevell is playing his way into a HC job next year. I see no reason to bad mouth a guy that's probably on to bigger and better things.
That said, I've been mostly a Bevell defender during his time here, but most of this season has taught me that Bevell doesn't seem to be able to construct a quick passing game with our short WRs and short QB. That lack of short passing game really killed us when the protection was the worst in the league. I think part of the reason it was the worst in the league was because teams had no reason to fear blitzing us, and in some cases blitzes looked to be automatic when Seattle showed certain looks. A sliver of that is on Wilson, but most of it's Bevell's responsibility.
When Bradley moved on, I celebrated it because I knew we could do better, maybe a lot better. When Bevell moves on, I'm optimistic that Pete will target an OC that can help Wilson grow into a Brees type QB that can master a quick throw offense and put his final exploitable weakness behind him. That's not to say I ever thought Bevell was terrible- he's actually quite good under ideal conditions. But we've seen a few games this year where defenses made those conditions impossible and it was a miracle every time Seattle won those games.
If Seattle can find an OC that turns Wilson into a QB who actually punishes the blitz instead of being punished by it, well, next season will be a hell of a lot less stressful.