Topic 502 staff or 502 1h and 489 1h for Windwalker
Baseline the 502/489 combo will be higher damage. Also don't forget that the second dancing steel proc gives a lot of extra damage.
Also, the staff has an obscene amount of hit on it, which doesn't mesh well with all of the hit that is on our gear this tier (especially the stuff on the Shado-Pan Assault vendor.) Lei Shen's polearm I might give a slightly different answer on, but generally dual wield will win hands down so long as the average item level is within 10 of the two hander.