World of warcraft, mage?

i was wondering what is the best spec for mage, i want a lot of damage, but i seem to not be doing a lot, in battlge grounds i usually get like 6k damage, and i see a lot of arcane mages' with like 10k but ive read acrane isnt very good ? has that changed? is it good now ? ive also heard fire does the most damage but i didnt really like fire the cast time took a bit, and i didnt really find i got that much damage with it, i am frost, but yeah so i was just wondering is arcane good now ? cuz a lot of people seem to be arcane and they always seem to have the highest damage in BG's