In original cata, xmog didn’t allow for the mace/axe/sword swapping that cata classic currently does. That was added in 5.2.0. It’s definitely a welcome change from original, but around the same time blizz implemented that change in then-retail, they also implemented a change that made a slew of main-hand only weapons into one-hand, so that they could be xmogged to either hand.
Any chance we could get that set of changes implemented into cata classic as well?