Solution:
Make the amount of mobs you have to kill depended on the class you are.
So for example if you are a priest you have to kill less mobs then an archer or thief.
Just some numbers for example:
* Thief kills 40 mobs
* Archer kills 40 mobs
* Wizard kills 25 mobs
* Warrior kills 20 mobs
* Priest kills 20 mobs
I believe this way every class will be able to finish the starcrest quest itself and have the full DR experience
