None of the Barbarian skills really offer any sort of elemental damage. I'm guessing that it's not really going to be a huge factor in higher difficulties, but maybe for PvP specific resistances could make a difference. Anyway, one thing I noticed is that when wielding a weapon with elemental damage, it actually gets transferred to the attack as part of the % weapon damage mod on the skill. From what I've been able to tell so far, the only skill that doesn't do this is Rend.
It's a little weird, especially for a skill like Ground Stomp - just because I'm holding a weapon that deals arcane damage, all my enemies now take arcane damage when I use Ground Stomp.
Whirlwind has a rune that makes it fire damage and basically doubles how much it does. Given that, I think having an elemental attack may be a great hindrance in a lot of cases. There must be a lot of resistances in later difficulties.
I think they have said that it won't be as excessive as it was in D2 Hell difficulty. I have yet to see if the Frozen, Molten, Electrified, (..etc) attributes actually give the monsters they enchant their respective elemental resistances.
It's a little weird, especially for a skill like Ground Stomp - just because I'm holding a weapon that deals arcane damage, all my enemies now take arcane damage when I use Ground Stomp.