Quote Originally Posted by shinytoy View Post
The issue here is that rogues are capable of tanking the current elite maps. Moreover, because the mobs are so easy for them, they're just standing in place, attacking and killing the mobs as fast or better than mages. Therefore, there is no need for any other class and we end up with mostly runs of 4 rogues
This is purely circumstantial and vary by guild, circle of friends and personal preference etc, this is where the game have limited control over.

Best way to limit stacking of a certain class will be the introduction of party buffs; where when you get all 3 class in a party the party leader will have to choose 1 of the buff bonus for the certain run/map: 10% damage, 10%exp, 10% speed, 10% armor, 10% mana or 10% hp. This will kinda push people to run and organize party where theres only 2 of the same class.

And the skill update will play a crucial role in future expansions, as the value of stats gets higher endgame stats makes skills overly boosted.