I think there should be an exotic two handed weapon.
There are 3 exotic 1 handed weapons and 0 exotic 2 handed melee weapons.
I know on a similar topic people want spears: http://forums.ddo.com/showthread.php?t=209342
I would be fine with a Scythe something. I just want it slightly better than the Martial variations to make it worth the feat.
2d4 Crits are x4 on 20 (similar to a heavy pick)
2d6 or 1d12 or 1d10 Crits are x3 on 19-20 (similar to a khopesh)
Another idea would be something like a Dire Mace where they could use the quaterstaff animation for it.