First of all, you are not a top arena player, please stop thinking you are. Any top player doesn't go around needing to inform others. Players like Homerjay, Quodan, Yudy... they stand out, and we recognize them as the top players. They don't need to blow their own trumpets.
Next, you are thirteen years old. I realize at your age, you may think you know everything, but I assure you, this is not the case. We've played this game for much longer, through its many iterations. We understand how classes were built, their purpose, and their mechanics.
You seem proud of your rating, and this is great for your confidence, I'm happy about that, but again you fail to understand why warriors are dominating ladders even without positive bugs. Mages are currently bugged, in that they cannot use polymorph, their main CC. As such, you don't see many frost mages at high ratings. Why does this matter you ask, my naive student? It is because Frost Mages are the ultimate counter to warriors. With them removed, warriors perform better in arenas. There are many other factors also at play, but this is just one of many.
Finally, I can see that my last post was informational for you. You now understand the difference between a difficult class, such as fire mage, with its many difficult mechanics, and an unviable class such as an arcane mage. At high rating, destruction warlocks are unviable, yes, but also not very difficult.
I think the thread's been answered. @OP play affliction for rating, play destruction for an easier class to manage. Demo is broken so don't bother.
@AntiWarrWrecker, if you are truly one of the best players, why not share your in game name? Top players are not so scared of showing who they are, they only play to be renowned throughout the realm.
Please also use better grammar, cancer does scare me, and many of your posts are killing my brain cells at a pace I don't appreciate. It's scary to think what can happen if I inevitably continue to read your posts @_@