Just to clarify, you're saying the person denying an undo is at fault for taking away their opponent's fun? I don't follow that logic. In the event that an undo is denied, %100 of the fault and responsibility lies on the person requesting the undo and they frankly need to suck it up. I agree with your first point that making some undo's automatic would be great as long as new info hasn't been revealed (and as long as it doesn't reset the 5 minute per action timer).