I hunted in the Silvies unit during archery season and had the same issue but figured it was due to the heat and incredible pressure. Lots of hunters. Some were shooting around camp just to make sure the elk knew we were there....
Silvies hasn't been the same since the Ochoco's went to a draw tag. I used to have areas there where I was in elk every time I went, and never had competition, not anymore. There are still some areas that may not have much preassure, but I am usually weekend hunting solo and don't want to try to pack a bull out of those places by myself. I would like to have a week off there someday just to see what its like now, I haven't hunted there in a few years now. I think the rifle hunting there is better than the bow hunting too. As far as the Ochoco's go, I have heard more bad reviews on the Ochoco bow hunt than good, I think people think that because its a draw hunt its better than OTC. The real reason (IMO) its a draw hunt is to reduce hunting preassure in the Ochocos, not because its superior hunting. If you don't want alot of competition, hunt the Cascades. Not nearly as many hunters and plenty of elk. Its just alot harder hunting than the central Oregon units. That's where I have been spending most of my elk hunting days lately. Rarely do I ever see another bow hunter in the Cascades, when I do, I don't have to go far to get away from them.