yes it does. the nados damage is always determined by the mainhand damage. the nado speed, however, is determined by the speed of the weapon which was swung last by an ordinary attack. this will on average be 50% mh, 50% oh.
therefore, the speed of tornadoes in the long run will be 0.5*(mainhand speed) + 0.5*(offhand speed).
thus, the 11% attack speed on offhand B are about equal to a 5.5% speed increase for the tornadoes.
on the other hand, there are experiments which suggest that about 80% of a double nado barbs damage come from tornadoes, only the rest from ww. so if we exclude str for the moment, the comparison would be roughly as follows: 0.8*1.055 + 0.2*538/728 = 0.991
hence, offhand B would do about 0.9% less damage than offhand A if both had the same amount of strength. if the 67 additional strength that offhand B offers over offhand A improve your dps by more than 0.9%, then offhand B yields the higher overall damage.
the difference should, however, not be very large. in comparison, offhand A offers 98 vit. and offhand A is also better if you use bash rather frequently to finish off mobs that run away.
to sum it up, i think that offhand B offers more damage, but only by an extremely narrow margin. i personally would thus use offhand A.
This post was edited by Black XistenZ on Sep 3 2012 12:12pm