Alright, I've decided on the new OC I'd like the Browns to target. And I'm finally at the point where he's the guy until he laughs in the Browns faces and hangs up the phone.
Vikings assistant Kevin Stefanski. He is currently the QB coach, but has held multiple position coach jobs on the offensive staff for twelve years. He's the son of NBA front office staple Ed Stefanski. Minnesota doesn't usually go after free agents, they develop draft picks. Stefanski has played a role in that development, along with getting Case Keenum up to speed after unexpected injuries to Bridgewater and then Bradford.
If the Browns are targeting a successful QB or other position coach to become the OC, the best are working with the successful quarterbacks right now and getting ready for the playoffs. I believe - no confirmation - Zampese is earmarked as the next QB coach, but the same reason he'd be a bad fit as an OC is the same reason another fired retread from another struggling team isn't the right move. Get a young guy who has been successful. They can also retain former Vikings running backs coach Kirby Wilson to work with him.
DeFilippo is the hottest name among QB coaches, but keep an eye on Stefanski.