Also, also, pretty much nullifies his Combat Challenge power since he can only take one immediate action per round. If he's always readying an action, then he's always got his immediate action consumed by his own standard action.
Yep, I'd decided that I was happy to accept that as a consequence of negating one enemy's attacks every round, but since I can't do that, readying just ain't such a good general tactic (although of course there will be specific circumstances where it will be useful).
Cheers, Al'Kelhar