The title states it all. i need to find a wow gold class i want to play soon. I WANT to play a dps caster, but so does every man and his mother. Should i play something else that is more needed, or should i play a mage, warlock, shadow priest???
If you want something with group flexibility, go Shadow Priest. Even speced Shadow, you can heal your average non heroic 5man, it's just a bit harder since you aren't speced for it.
Play what you want.
all the classes are fun. prepare to waste days of your life finding a class. i had 66 days played on my first mage when i went back to finally finish leveling my priest, then he was my main, then i switched again, and again, eventually rerolling this mage on deathwing.

don't think of it as time wasted, its time playing wow, that is all.
This is something you can only decide for yourself.