If John Harbaugh gets the axe in Baltimore, he's at the top of my list. He puts good staffs together and lets them do their job. He has a 10-5 record in the playoffs and has never gone one and done in the postseason. His success obviously dropped off after 2012, however people don't consider what a millstone Flacco was over that span.
Flacco's cap hits were comparable to Rodgers'-- a similar situation in which you have a big bite out of the apple from one player. That can work if said player is Aaron Rodgers. But Flacco was straight up bad after signing that first big extension. So Harbaugh was saddled with a QB who was pretty much a competitive disadvantage on the field, and yet was paid like he was elite. He had to coach around it, and he did so to the tune of about .500 football since 2013.
However, when he didn't have that weighing him down, he had 54 wins in five seasons, 5 straight PO appearances, a 9-4 PO record, and a SB victory. Ozzie Newsome was a great drafting GM for most of Harbaugh's tenure, but Harbaugh's staff also did an excellent job of developing talent. And he's clearly comfortable working in a situation where the FO has personnel control.
Mike Pettine coached under Harbaugh/Ryan in 2008, so there is a connection there already and good reason to think that Harbaugh would keep him, which I would like for the sake of continuity and because I've seen strides under Pettine.