There is no reason why a Barbarian should not be able to wield two "2-handed" weapons, and suffer some kind of stat penalty to balance the mechanics (as many have said here).
For the purpose of aesthetics, if nothing else, I agree completely with the OP - Barbarians should be able to dual-wield 2-handed weapons.
Be more constructive or shut the hell up.
You know it's hard to balance duel wielding 2handers in D3 because D3's game mechanics is totally different than D2. They've got enough headache in how much weapon dmg each skill deals, since every skill's damage comes from gear+weapon stats. You really think they'll go through all the trouble bringing two 2handers into the equation?
If it's just for the pure purpose of aesthetics, they can just make the rune sword look bigger in game, as big as the warlord sword. That saves 'em lots of trouble and makes you happy. Is this idea constructive for ya?