Kilroy was here
...Of course, when a deputy is in play, not a renegade, the outlaws have a hard job, since it's two vs two and the sheriff has more life points. Maybe that imbalance is a fatal flaw of this proposal, ...
I think this would indeed be a fatal flaw. The renegade has it hard but not much harder than the sheriff. I think you could swap in a renegade for a deputy at higher player counts but doing it the the other way will always make it too hard for the Outlaws. Although some would argue that the outlaws have the easiest goal, swinging it the other way tips the balance too far. Any standoff between the sheriff and renegades is always a battle of last one standing with the renegades trying to kill each other first but also keep the sheriff alive - but week enough to kill. Swap just one of those for a deputy and the sheriff's team should win easily.