I think it's interesting that most here want fox gone, but on the bears unofficial Reddit (probably bigger than this place) the tone is completely the opposite.
Personally, I want him gone because of Trubisky. Fox is a product of his coordinators, and while he has a history of getting very good coordinators, I have to feel with Loggains that his luck may have run out. PLUS, if he is retained, he is still most likely a 1 year coach whether or not he gets a one year extension, so even if he were to fire Loggains, it seems unlikely that he is able to make a phone call and get the next young top O coordinator.
On the other hand, you have an opportunity here with a good young defense, and a developmental quarterback. Plus you can assume that help in terms of weapons will be coming. I think this offseason should be the time to act. Fire fox, and get someone that has an established track record of offensive success, and/or quarterback development.
Don't squander another year of Trubisky. I'm comfortable saying that another year of Fox will do just that. When Pace drafted a Quarterback, he got a lot of equity with me. When looking at the Y1-Y2 jumps of last year's draft class, I have to be confident that Pace isn't tone deaf enough to keep a coach that is unlikely to allow a young QB to realize his potential.