Damage will be lower and more predictable
There are about 8 billion blue posts on this issue. Even if this isn't initially true and we have some crazy burst damage, it's going to be adjusted rapidly in the beginning of the season. Blizzard is not going to allow another Season 5 (Burst
Wrath of the Lich King Death Knight) to obliterate all our PvP joy.
After all, arena representation dropped 65 percent from Season 4 to Season 5. That's a ridiculous drop in numbers, especially considering that more people were playing after the release of Wrath. In fact, I wouldn't be surprised if Blizzard goes a bit overboard and makes damage even more comparatively lower than in Season 1 of The Burning Crusade! Rated battlegrounds are going to cause lots of 2v1 and 3v1 situations; people are going to get blown up quickly and complain about burst damage, even if arena balance is completely fine.
I wouldn't mind a giant damage philosophy shift, either. The longer games go on, the more time exceptional players have to turn the battle in their favor. Even the best players can't succeed if a bunch of crits make their life total go from 100 percent to 0 percent in a global cooldown.
Healing will be lower
The Burning Crusade arena (Season 1 through Season 4) had a pretty awesome damage balance. Unfortunately, healing was overpowered as all get-out. Restoration druids, particularly, were able to run circles around opponents while pushing two or three HoTs to keep their team fully topped off. Classes that were able to deal with restoration druids were consistently successful in The Burning Crusade. It helped even more if these classes had infinite energy resource mechanics (because hey, running low on mana determined lots of match outcomes back then).
Blizzard isn't going to let overpowered healing reign again. Healing is going to take much more effort (and mana) to keep your team at a high health. I'm anticipating lots of battles being won by the healer who is most efficient with his mana instead of the one who can throw in crowd control and burst damage whenever possible. This is a good thing and something healers should look forward to.
Drain strategies will be effective
Drain Mana-type abilities sucked for the vast majority of Wrath of the Lich King. Mana Burn was the only one that was halfway decent, and only in certain matchups. Who wants to kill someone's mana when you can just kill them?
Because healing will be consuming more mana and damage will be much lower, drain strategies will see a giant power rise when Cataclysm arena appears. This is also welcome in my book; Wrath PvP has become increasingly linear, and it will help overall arena enjoyability to diversify winning strategies.
I wouldn't expect to see a lot of drain comp 5v5s, but it might happen. Double healer (with a priest for Mana Burn) 3v3s will be much more common.
Crowd control will be weaker and slightly less relevant
Crowd control chains were incredibly important in The Burning Crusade. It was almost a necessity to hit the opposing healer up with 3x Cyclone, 3x Fear, 3x Polymorph rotations just to kill a single person. Wow. Of course, this was because healing was overpowered.
In Wrath, crowd control isn't necessary to achieve a kill, it just makes it way easier. Just hitting one crowd control on an enemy healer is enough to kill an enemy because that 10-second window (or less) is all you need to drop someone from 100 percent to dead.
With healing being far less powerful in Cataclysm than in Wrath and damage being toned down a good bit, we'll hopefully see crowd control in a sweet spot in between incredibly powerful and necessary.
On a similar note, effective crowd control like Fear is being increased from a 1.5-second cast time to a 2.0-second cast time (at least, last I checked; I don't believe this change has been reverted). While this is largely to counter haste stacking, it makes enemy crowd control much more predictable and just generally better for the game. No one wants to get feared without having a way to react before the cast time goes off.
Gameplay disclaimer: OK, so while some of these gameplay predictions might seem obvious, they're really not. I'll warn you in advance that if you read a lot of blue posts about PvP, you might see some of my predictions lining up with what's being said from the developers. However, this isn't always the case -- hence the incoming tangent:
In late Season 5, Ghostcrawler went on a bit of a tirade trying to assure everyone that burst damage was not spiraling out of control and that once the majority of players geared up, resilience would fix it.
I predicted it wouldn't happen. It didn't happen. Yay, I was right.
While I'm a bit more in agreement this time around with developers, I truly feel they understand PvP better now that they have eight seasons of arena (and some giant mistakes that came with it, particularly in the last four) under their belts.
Want to ascend the arena ladders faster than a fireman playing
Donkey Kong? Read Blood Sport for pointers on arena play. Don't miss our interviews with successful arena PvPers, and see The Art of War(craft) for the inside line on battlegrounds and world PvP.