I can see the OPness of arcane right now. Did 487k damage, 32 KBs, 87HKs, and 2 deaths in AV a few days ago. But I also see people learning to deal with us. Our instant damage has been buffed up alot, but our squishiness hasn't. Once people learn that we need to be dealt with quickly then I don't think they'll be having as much of a issue. I feel it's as it should be.
I've done probably around 50 BGs as arcane (in S3/S4 btw) and dueled every class and spec I could think of. The two classes that I could see having the biggest issue now are locks and shams. Locks can only complain becuase they can't walk all over us anymore, and that's somthing they'll have to get used too. Shams lost the biggest, and probably only advantage they had, earth shock. They can no longer stop every other cast we do and that's really seeming to **** them off.
Warriors were always pretty easy but I find are actually a bit harder now. You can't get away with letting them get close to you as much as you used to. No more R1 frostbolt and /dance.
Ret is the same as warriors at the moment, if you can keep away from them it's cake, but let them come in 2 or 3 times and your done. Slow is your friend. I've seen rets run into a group of 2 or 3 people without fear, then run away from me. But after the next patch they'll be bubble-hearthers again I'm sure.
Rogues really arent much of a change for me. They were always a close fight as frost, always going down to the wire. Now we just have another spec to PVP with. Still about 50/50 for me. But they have cheat death, not cheat arcane barrage, which apperently hits harder then death.
The burst and slow really helps against druids, they can still hump poles but can't get away nearly as easy as they used to with slow. They are yet to see my trink/AP/PoM/fireball hitting them in the face though. Once they learn that 100% HP is good and 50% HP is death then they'll be back to their pole humping days. (although they are kind of a decent 2s partner now)
Shams went from a pre-3.0, frost spec, 30 sec fight to a post-3.0, arcane spec, 15 sec fight. They sucked at PVP then and they suck now (not dissing on the shams, my main is one so I do feel the pain)
Spriests are hard to come by in PVP gear on my server so I've really only faced them in BGs. But as far as I can tell I don't blow them up any harder and faster then I did as frost.
Fighting hunters is still a DPS war to see who can kill the other first. I guess a little eaiser now since I don't have to cast much save for arcane blast, but no pushback on that. It's like I have IV all the time now... but they have a pet, so ***** em.
Locks are fun now for a few reasons. First is I have WotF, trink, and IB. Second becuase they all speced into felguard. And third because their new shapeshift toy doesn't do crap for them against spells. But I hear they do better against rogues... so good for them.