Obviously WS will work better the more tanky targets you are hitting, so if people are stacking armor (6v6?) then this will be the best route.
Str seems to be the best all around because you aren't going to get to softcap at current gear levels without using RR and/or some str talismans + the 2 available str tactics Slayer has access too.
Armor seems great as an order player in the current meta of TANK TANK TANK TANK HEALER HEALER, but is it viable to still pull off kills? I guess it wouldn't matter when talking survivability against sorcs, since the other 2 don't really help with that element either.
I guess it really comes down to, get 2 sets of gear!

All comments and concerns appreciated, thanks for taking the time!