Well, it depends what areas....
Tombs
Barrage pet groups with 1 or 2 monks
Bip MM bomber, SS, Bonder, Healer, Tank
Solo Assassin
SF Oro
MM, nuker, bonder, healer, Tank
FoW
MM, nuker, bonder, healer, Tank
Some solo builds here as well, A, N, E, P
UW
Lots of solo builds in use here: Rt, E, W, Mo, A
55/SS Famine farming
Duo & Solo Trappers
DoA
Solo and teams builds
Nukers, bonder, healer, Tank
Solo builds here too, E, N, Rt, R, Mo
Urgoz
BiP, MM, Bonder, Healer, Rt Spirit Spammer, Tank, Nukers
Barrage / pet groups
Trappers
The Deep
Nukers, Tanks, SS, BiP, Monks.
Some variations on this as well, W can solo to a certain point, etc.
As you can see, most classes are used pretty heavily. In almost all cases you can use a Dervish as the Tank.
The class that suffers the most from these builds are likely to be the Paragon. There is a FoW solo build for it (see above).
The Paragon is a very good support char, which can always be used in almost any party.
Biggest stumbling block would be for people to accept them, because if it's not on "the wiki" people dont want to try it....
if you get my meaning
