Spending a lot of time on WS, I've noticed at lvl 18/19, it seems to me the order of who rules WS (in general)....
- Barbs and Hoxes (pvp gods at this lvl)
- Bear shamans (decent ones) next
- Conqs and guards next
- necros and rangers next
- then sins and demos (though demos/casters can handle necros pretty easily)
- dts, tos, and poms last
Of course there are exceptions - vets who jump on their lowbies can play well on any class.