Ok, play against a Knight/warlock with full matched gear for the class and you will see the same dmg. This game is pay to win, thats how it works.
And not every player has same dmg with mage/warrior. It is about our str cloth gear. If we spend too many diamonds to make a powerful str cloth gear, our dmg should be high. We are simply making 2 gears to play mage/warrior. Why should we spend so many diamonds if our damage will not be high ?