Originally Posted by
StRaIgHtJaCkEt
Un, no. You must not have much knoweldge about other classes. Shadow Priests are worst class in the game for belts and are the worst caster in the game when it comes to mobility on fights.
If you ask a shadow priest to go on belt they always have to save DP3, which means their dps priority through out the fight becomes significant hampered. They Could Save Mind Spike charges.. DP3.. but this is really suboptimal. Where as you could just ask a warlock to go on the belt and cast while moving.
Shadow Priests
-Have no teleport ability.
-They cannot cast while moving(unless they have procs available) - Warlocks can with Kiljadean Cunning talent.
-They cannot channel mind flay while moving(significant for things like DP3)
Elemental shamans and Warlocks are the best caster to put on the belt and in general elemental shaman, hunter, warlock, are top choices for belt teams for ranged options. Priest/mage should be last option for belt in almost any group that wants to optimize performance of the entire raid.
Now if a SP/Mage wants to hop on the belt because its fun and they're good at it and it doesnt hamper raid performance then good for them. But in general its just not an optimal strategy.