To be honest, as you stated it is all on you, what you find fun... it doesnt matter which class is the most overpowered, which is the most underpowered etc. its all about what you enjoy most.
DPS with crowd control = warrior
DPS without being spotted = Rifleman
AoE Dps = Warlock
Healing / Support = Cleric
Hiding with Lockdowns = Dual Gunner
Pdef and Mdef buffs? = Paladin
My advise would be to just create one of each character and level them to.... lets just say 70 (without jumpstarting), and using 3 hour caelium extracts from the talent merchant, see which class you enjoy most as i believe by 70 you should get a general idea of most classes by then (id say you probably wont with warlocks but meh), and choose on which one you enjoy the most... maybe alot longer, but dedicated people grind to 70 in a matter of days on this game... perhaps less.