Resistances and vulnerabilities on Aardwolf can be variable, rather than having single 'flags' for whether or not a character is resistant or vulnerable to a damage type. This leads to a wider range of options for spells and equipment options as well as more diverse races.
The damage types 'magic' and 'weapon' no longer exist as generic types. A character is either resistant or vulnerable to a damage type regardless of the source of the damage. 'Magic' is now a standard damage type just like fire and acid. The 'weapon' type has been removed completely. There is also a new damage type 'shadow' which is a counterpart to light.
A number of resistance related spells that set resistance flags have been modified to provide varying amounts of resistance based on stats. Again, remember that the affects of these spells will now add to any resistance provided by the Aardwolf Breastplate and any other resistance items. This new system allows for a much wider range of resistance affecting spells and maladictions in the future.
Note that resistance is on a curve - any additional resistance you get will always help your character, but doubling your resistance points will not necessarily double the amount of protection it provides.