Most likely in a MMO in something like this, everyone is going to choose the most basic and obvious class in the game as most popular, and that would be warrior. The big brutes and jack asses running around with axes, hammers, spears and big and long-ass two-handed swords and other brutal melee crap coming out their wazoo, dealing slow but powerful blows to all the enemies they smite.
I don't know for sure, but with assassin, just like the song goes, you get the best of both worlds.
best grinding class is mage..with in less than 24 hours of gameplay i got to lvl 40 on a fan mage..but they arent so good in pvp cause they run out of mana really fafst but its best just to test and find out which suits u best