Ive seen some pure tank dh with crazy thorn build.(iirc his thorn is about 13k, and hes still stacking for more @_@)
Basically he just stand still, put setry and loh with caltrops, and the rare occasion against ranged use grenades.

His weakness are knockbacks and fear as they force him away from his sentry haha.

As far as loh skill goes, dh is the most imba with caltrops proccing every 1/2 sec I think.
Dh also have grenade skill which have loh multiplier by 3.