Night of Reod,
If we didn't have so many feats, for example, a bonus feat for every single level for fighters on top of one per three levels, I would say that the feat investment for two weapon users to achieve +7 ac is daunting. But, since we do, it's not.
You can keep your systems and talk of shields with DR (SO WHAT? GET AN ADAMANTINE CHAIN SHIRT!) and keep your talk of dispellable temporary effects, the REAL question is, is this a roleplay server? If so, how are we to roleplay that the guy with a dagger in his left hand is able to block more blows than the guy with the giant piece of steel covering half his body? Not to mention, as someone else pointed out, apparently deflecting arrows with that dagger better than the guy with the huge shield does?
It seems I missed this. The amount of DR I was referring to is "virtual" and not actual DR, and 50% DR is much, much more impactful than the 3 DR adamantine offers, not to mention adamantine is fairly rare and "so what, get an adamantine chainmail" is not really a valid balance argument.
Varnishes and magic vestment spells are not dispellable temporary effects, as they effect the items and not the character, dispell spells on the character will not effect them.
As for this being a roleplaying server, of course it is, which is why you are free to, and even encouraged to, roleplay your shield user in any way you want so long as it makes sense and doesn't involve cheesing. This is not a discussion about how to roleplay shields, this is a discussion about game balance.
As for realism, the guy with the giant piece of steel covering half his body makes absolutely no sense whatsoever. Having such a big shield that weighs 45 lbs would not only be extremely cumbersome and tiring, but it would also be too slow to be useful for parrying, and it would also make it really hard to use body mechanics and your body weight when throwing cuts/jabs, making your offence and defence much weaker. Which is why there are pretty much no accounts of these kinds of shields being used in actual melee historically. I believe the only thing that comes close is big wooden shields, but those were made out of wood and not metal, and they were mainly to defend against arrows and stones and were discarded once melee started. Shields that big were not used in in melee in Medieval warfare, which is what DnD combat tries to "emulate," if you can call it that. The tower shield in DnD is inspired by the pavise, which was used by crossbowmen as cover to reload behind, and even those were occasionally carried by a groom because of how cumbersome they were and how difficult they made moving around, let alone fighting. That is not the only historical/logical inconsistency in DnD system as well. Holding two swords doesn't really make you attack any faster, for example. Rapiers are not light, they are quite often heavier than arming swords, which DnD 3.5 calls "longsword" even though most historical longswords were made with two handed usage in mind. The list goes on and on. Both DnD and NWN are not realistic and they are definitely not historically accurate, and I think it is not very sensible to use realism as argument for something that is inherently not realistic in many aspects, and even then, this is a game and we are discussing game balance, and game balance is separate from concern of realism. In any game where you have a competitive mechanic, which NWN very much does, I believe you have to try to put game balance above other things.