As for Tomlin having Cowher's team and whatnot, that's might be true, but Tomlin is still building his team. He's only been here 3 years. With him, we've gotten Woodley, Timmons, Mendenhall, Wallace, Sepulveda, Mewelde, Keyaron, and Ziggy, all of whom are solid players.
And you could say that Whisenhunt took Dennis Green's team (or whoever was there before him) to the Superbowl. Warner was already there, as was Fitzgerald, Boldin, James, Dansby, Dockett, Wilson, and others, all of whom were major contributors in their Superbowl run.
We've been a defense-first team for a long while, so it would have been surprising to see an offensive-minded guy as our HC. Plus, Ben didn't get along with him, so what's the point of having an offensive-oriented team when the franchise QB doesn't like the coach?
We don't need Whiz as head coach. We just have to replace Arians (or hope he gets his stuff straight).