The game is completely playable in its current state you big baby
With a warrior yes. I don't think there are any glitches with the warrior class.
I can't remember what the rogue exploit was but I think it had something to do with dodging. You can also fly as the Ninja specialization.
Rangers: crossbow right click spam, Retreat+glider very fast traveling, boomerangs are OP, Scout's Swiftness crash servers.
Water mage: OP as stuff since one of the attacks creates an area on the ground that continually damages enemies and heals you. You spam that to win.
The game needs much more features for it o be enjoyable for me.