I think a big concern with Doom is his size. How long before injuries start becoming the rule with him rather than the exception? Taking the beating that he does at his size?
He's been dinged up off and on the past few years.
The JJ Watt comparison doesn't hold water IMO though. Watt controls a game as both a run stopper and a pass rusher. His size allows that.
I don't want to see Doom go either but I think you can only have about 2 untouchables on a football team and in Denver it's PFM and Von. Outside of those two, who else on this team is indispensible? Champ? He may be the closest.