So, after playing around for a bit, I can't honestly seem to find a good reason to Dual Wield. I mean, yes, 15% IAS so it nets a damage increase ... but only if the weapons are practically identical (within ~10%). Honestly, off-handing a Shield with sockets for your +Stat Gems will ultimately be a greater damage increase in the long run plus you'll die a lot less often.
@Crafting - The rares you can make from it are pretty much good guaranteed options for the level they are. The gold cost is practically irrelevant, honestly. If you just farm the AH, though, I suppose you'll not find it all that useful but ... you're probably buying crafted items off the AH anyway.