Arcane is still very viable though, you just have to be more conscientious of how many Arcane Charge stacks you are keeping. Arcane now has Cauterize without having to spec Fire, which IMO makes us more magical. AM now stacks twice and we now have a DoT just like Fire (Nether Temptest), so expect to see a lot more purple silly-string coming out of us.
And our tele's, ports, and food conjures don't require reagents anymore, which is really cool. But I'll still be charging for ports though. My new hobby when I'm bored is skydiving, free-falling 2000 feet and popping Slow Fall 1 second before you hit the ground is sooo fun!!!
At 90 the DPS spread between Arcane, Frost, and Fire is supposed to be about 2%, which means you can expect us to continue topping the DPS charts in raids just like in Cata. I still expect there to be noobs whom continue to complain that our class is OP/too simple, but what can I say? Haters gonna hate. =D