Well... first, bluntly, Daedroth's are big, slow, hulking beasts - you should be able to kill one without ever getting hit at all. Armor shouldn't even be an issue in a fight with something like a Daedroth (and in fact, I have one claymore fighter who doesn't have any armor/enchantment protection at all, as a largely successful test of just that idea).
Standing in front of an opponent and spamming attack is never a good strategy, no matter the character or the weapon. It's good that your warrior doesn't like to block - that's a poor strategy with a two-handed weapon anyway - but he should be taking advantage of the benefits of a two-handed weapon, primary among which is reach. By moving around, keeping his distance and either stepping in long enough to get off an attack or attacking the opponent the instant it's close enough, he should be able to win the battle without even getting hit. I've tried it both ways and they're about equal really - waiting for the opponent to advance to you requires positioning oneself so that other potential opponents can't get to you (in a tunnel, for instance), but makes it easier to time power attacks for much more damage, while moving around allows you to battle multiple opponents even in open areas, but takes more practice and makes power attacks difficult at best.
My other suggestion would be to enchant that claymore. Dwarven isn't the best you can get by any stetch, but that's actually of less consequence - the difference between the base damage of the various weapons isn't all that great in the long run, particularly since a good Grand Soul enchantment of elemental damage (equal amounts of all three is the most effective) will do far more damage than the base damage of the weapon anyway, so the few extra points you might pick up by trading up aren't that big a deal. That said though, the extra durability of better weapons might make a difference. Though with a good enchantment, you won't have to hit anywhere near as many times, so you might be able to get by with Dwarven anyway.