Personally, I definitely prefer this system:
Jake wrote:with the exception of poison, the only difference between any of these is whether or not a character is vulnerable or immune to an attack
over this one, in which specific attack types get inherent bonuses against specific defences:
Vryl wrote:Armor: Fire will soften metal and scorch leather, so it would make sense for this to decrease armor defense. Lightning, on the other hand, conducts well through metal - you could make a small portion of damage go straight through armor defense.
Dexterity: As stated, ice could slow reflexes and muscle responses, decreasing defense. It's easy to slip on wet floors and hard to stay in the air with sodden wings, so water could deal a little unavoidable damage just like lightning does with armor.
Ward: Air can cause a long-term distraction by getting grit into a mage's eye, while rock can cause some damage because unlike pretty much everything else the rock wouldn't necessarily slide off the ward. The mage has to expend extra effort to push the rock off once it's been stopped.
for two reasons:
1: It seems to allow for a wider variety of total defences, as what a unit is vulnerable to and what it's defence type is are independent - the pixies use dexterity defences and are vulnerable to fire, while a swiftly flowing water elemental might also use dexterity but be vulnerable to ice (because it can be frozen). Any defence can be paired with any vulnerability (or immunity, for that matter), based on what makes sense for the creature in question. If lightning, as suggested, had an inherent bonus against armour, that's no longer entirely true, and it means any armour-based creature with lightning immunity is stronger than an otherwise identical creature with a different immunity, making balance more complicated for what seems like little gain.
2: I've very rarely seen a system in which the bonuses certain attacks get against certain defences actually make sense in practice beyond the most simple examples. For example, the suggested logic by which fire and lightning attacks might have a built-in bonus against armour defences makes sense in the given context of metal & leather armour, but armour in the game could (and I strongly suspect will) be much more broad and include things like the hard scales of a dragon, the stone body of a golem, or the shell of a noble snailfolk adventurer, none of which make "fit" with the logic of those attacks getting the bonus against them.
TL;DR: I'd much prefer that (for example) a knight in copper armour be using the armour defence and separately have a vulnerability to lighting as two different properties of the unit, than a broad rule that lightning attacks always get some bonus against the armour defence, because it means more combinations of defence/weakness and allows each individual creature to make sense for it's own abilities while keeping the individual systems simpler and easier to understand.