This is absolutely not worth the effort on a warrior. You have to unequip the 2 hander and switch it with a 1 hander in a bag then equip the 1 hander in the off hand. Then the reverse. If you don't turn attack off, then your offhand will fire immediately with H2H damage (which maxes out at 100 for a warrior) when you unequip the 2h, so that's why you have to turn attack off.
Being super hasted (41% haste item + VoG
survival race ) will outweigh any benefit of weapon twisting on a warrior. I think that's why OP adds the caveat that it only works while leveling because haste is level capped, but this would not be beneficial while raiding at level 60.
There might be minimal gains to doing this on a warrior while leveling or raiding sub60, but 1 swing out of order would ruin the whole thing and result in less DPS than if you had just turned on attack and AFKed the whole fight.
Monk is a different story, though, for 2 reasons: 1) Their H2H cap is higher, and 2) epic goes into fist slot, so you don't have to use two weapons while twisting or even turn attack off. Just swing with 2h, unequip, swing with fist, then reequip.