Well, he's going to forge some nice weapons (Magebane + Summit is awesome): that's more defence with some mean fighting power.
I have heard that area attacks completely bypass defence, so you might wish to make sure there aren't any such item in the game before going too high on defence. I think a couple artifacts have this effect, but I could be wrong (I have seen more of them in CB 5.2 or so). I haven't had the opportunity of checking that, though, but I know my 52 defence would have very much disliked that sort of trick.
