I like how you changed your tone from to
Nice to see you now understand what viability is, and what a difficult class is due to mechanics.
As for my rating, unlike you, I have nothing to prove to anyone. Only people that have never accomplished anything go around talking about their rating. Its quite clear to me that you are:
a) new to this game
b) new to this server
and c) are 13 years old.
Putting all this together, your replies show the world who you are behind the keyboard, a thirteen year old seeking attention by claiming to be some pro player, when in reality, you are just one of the many warrior players that got their ratings boosted thanks to bugs.
When the armory launches, we'll know for ourselves just how "pro" you are.
Until then, keep attention seeking my friend :)
At OP, sorry for taking this thread off-topic. I really do regret all my posts here.
Destruction warlocks are an easier class to play than affliction warlock. They have been since TBC. That said, destruction is just not viable at high rating because of the long cast times, and the high mobility in MoP. In WotLK Destruction warlocks actually work pretty darn well, but not in MoP.
Demonology tends to be a PvE spec (IIRC from retail charts), but they are so bugged here that a warrior auto attacking will likely outdps them.
So, tl;dr, go destruction for easier time, affliction if you aim to go high in ratings.