This is a dead horse and a bad question. RR is going to be missed. No doubt, he is a top spread mind. The defensive staff will not be missed. This wasn't a black or white "We're going to fire a guy and get a 100% upgrade", this was more of a "trading up" kind of thing.
Any time the offense stalls out due to a bad scheme or confusion this season, just close your eyes and imagine the soft fur of a teddy bear being rubbed over your face. That should calm you down.