Haven't seen anything yet on Theo's PvP Rogue FAQ pertaining to Poison use in Arena, so just throwing this out there...
Being 20/0/41, I tend to go with the widely accepted Wounding-Mainhand/Crippling-Offhand.
But what about certain comps like a pair of Mages (Mind Numbing?) and/or Dual DPS?
Or what about certain Pally comps that call for you to FF on the pally, should Mindnumbing be used over Wounding to slow his Flash's down for kicks/gouges?
Just throwing this out there, feel free to give your input.