Well WW stuff on Noxic supposedly says there's a 5% dps increase from DW...
But besides that
http://us.battle.net/wow/en/characte...panda/advanced
I don't know how, or why, but I've definitely had EB stacks fall off due to lack of white-hit for 30s. Well, I do know how or why... sometimes ridiculous RNG, sometimes it's because of a tank swap or mechanics force me to move or not be able to melee for a bit... but DW would certainly clean that up a bit with the more frequent white hit crits.
Either that or they should buff the 2H EB stack duration to 90s, since we get stacksx3 for crits with 2H.
Also I really need to figure out a way to glyph roll as tank and not kill the raid for tank swapping fights... having to throttle DPS with an undergeared OT is brutal sometimes.