Mostly dps specializations, dots with poisons, critical hits in the right places, always avoiding aggro, it could also have some specialization to be a kind of semi-support stealing equipment from mobs, decreasing their weapon damage, shields to remove defense or armor to remove stats (in case of more complexity make combo with other classes ej: hunter/warrior/rogue [remove a helmet = Increases neck damage/headshots damage etc])
And
in addition setting traps or using gadgets that benefit the team (smoke for
invisibility in area / Blind mobs,
some
slowing poison to place in an area and run from mobs)
and
finally a specialization that separates itself from traditional rogues by
removing his invisibility for the use of swords / Katanas and based more on
speed instead of stealth even so taking advantage of poison and gadgets (to differentiate
from some classes like an offensive warrior)