|I have ItemRack set up to switch between 2h and 1h+shield depending on stance (berserk & battle use 2h). When my opponent dodges, I switch to battle stance to Overpower him, but instead of equipping my 2h, ItemRack un-equips my shield and then switches my 1h for my 2h thereby doubling the cooldown of the item switch.
As I figure it, ItemRack should merely equip the 2h weapon from the get-go, since WoW will automatically remove the shield.
PS. I tried using the "Overpower" event, but it didn't seem to work. /shrug
Other than that, this is by far the greatest equipment addon I've tried. :D