The last time we got some new Classskills is over a decade ago. Many players lack the motivation to level up because the are few reasons to do. New Skills at level 170 or 180 for example would greatly reward the efford of leveling that far and increase the motivation to do so. That would of course also increase the amount of players to cash for Amps.
New Skills would provide a great possibility to balances the classes a bit more. Here are some Ideas:
Mentalist: "Paralysis of Lamal"
-Decreases targets blockrate by 25%
Forcemaster: "Wrath of the old Gods"
-Increases damage of critical hits by 50%
Seraph: "Blessed Weapons"
-Doubles the damage of your groupmembers for 3 seconds
Seraph: "Magical Shield"
-Creates a magical shield for your groupmembers that`ll absorb the next hit
Harlequin: "Acrobats Legs"
-Increases your movementspeed by 50% for 5 Minutes