Weapon for Werewolf Druid

[FenrisWulf]

I personally would go for the IK Maul, but then again, I don't know a lot about your Colossus Blade. Two things I can guess, though:

Your Colossus Blade is dealing around 118-301 damage (should most likely be a bit less, but I don't know exactly what jewels you socketed).
It has less than 50% IAS.

In comparison, the IK Maul should deal around 234-321 damage, is faster (by virtue of WIAS and weapon type), gains 1.1% ED per point in Strength, has a nice bit of extra damage against Demons and Undead, and deals up to 40% Crushing Blow. If you place a Shael or IAS jewel in the IK Maul's socket, it will be swinging at 9/5/5/5/5 (thanks, TheDragoon!). I really don't see how the CCB can even compare. :D Leave it on your Barb.

IK will serve you fine all the way through Hell, easily. It's a great weapon. However, as a Shifting Druid, you'll need some sort of PI switch; I would recommend Baranar's Star and Tiamat's Rebuke, obviously, but if you don't have these handy, an Elemental Damage Wand/Dagger/Sword, either Magical or Socketed, will work decently well, too.