So what have MOP done to shadow priest well lets have a look at it.
Shadow Orb - Empowered shadow management:
removed no longer have to keep track of this buff making sure that our dots is put up when this buff is active is no longer needed.
New Mastery:
Gives you periodic Shadow damage spells ( % ) chance to deal damage twice, each time they deal damage.
My opinion on this:
Makes the class less fun and challenging to play being able to handle this buff correct was rewarding making shadow priest more unique. The new mastery simplify shadow priest removing a huge skill factor thereby making the spec way less rewarding.
Dark Evangelism / Dark Archangel management:
So Dark Archangel(2 min CD up from 1.5 min) is now optional and does not generate Dark Evangelism.
My opinion on this:
Yet another skill factor removed no management required and most likely not a talent that will be picked only for occasional fights.
This two changes out of many that in my opinion destroys a lot of skill and challenge with the class.
PS: sorry for my grammar and spelling.
Post on official forum.
eu.battle.net/wow/en/forum/topic/4551308916#1