This is exactly the boat I am in. Considering his role as an Offensive minded coach, after this season you have to look at it like this:
Did you make the playoffs in your first two seasons? No.
Okay, well is our team better in your specialty area? No.
Is it because of a poor roster, or truly extenuating circumstances? No.
Well, what exactly DID you do?
The answer to that last question is how you make your decision. If Marone truly made an overall impact in player morale that resulted in his 8-8 season, then MAYBE he deserves to be kept. There is no way, however the offensive coordinator can be retained with his answers all being "no," and having done nothing to improve his side of the ball.
Looking at this any other way is not pragmatic, and just makes excuses in place of results.