Rogues are great, and can be played both as casters or melees.
melee:Weapon: Daggers! Rogues have highest dex of all feeder-classes, and Daggers profit most from dex.
How to stat: all Dex! You get dmg, better crits + you receive less severe crits from mobs

you have a great tanking potential!
Gear: Damage-Setup: EE-Dagger, Dex-Armor, Dex-Charm

most damage output
Tank-Setup: EE-Dagger, EE-Scale, Int/vita-Charm (increase armor-values) -->Very often a good Tank is needed in groups, and this Setup is a very efficient and cheap way to help the group. Very often tanks are more valuable than another good damage dealer!
Caster:How to stat: all Int! You get dmg, better crits + you receive less magical damage--> you have a great tanking potential as well!
Gear: Damage-Setup: Int-Weapon (type does not matter, whatever is cheapest), Int-Armor (preferably scale/leather-->cheaper), EE-Charm

most damage output
Tank-Setup: Int/hm-Weapon, EE-Scale, Int/vita/Dex-Charm (increase armor-values), EE-Heal in Acc-slot -->You are now healer/tank. Very valuable in most groups
As you can see, the rouge can adapt to every situation in catas, and is thus the best feeder class imo.