I ended up playing 50-60~ games of HLS and RLS on the level 90 Arena Pass last night, and I had a few thoughts.
1) BM Hunters - How did this get past... ALPHA? The first comp I tried was HLS, and I could not BELIEVE what I was seeing. I could be across the map in a CC and if my hunter popped his ZOO he would 100-0 something in 1-2 seconds, 2 seconds being a slower kill. No dots or damage from me whatsoever, while I sit in a full cyclone. There is no excuse for imbalances like that, other than Blizzard... being Blizzard I guess.
2) Mage control - With the dispel change, I think mages are grossly overpowered. A mage can sheep me, and start casting a sheep on my partner, so that as I get dispelled my partner gets to sit a full sheep. Alternatively, the mage can just sheep someone, have the healer dispel it, and then pop every one of his cds and deep + frost bomb something. I think something NEEDS to be changed about how mages work after the dispel change.
I actually didn't have a problem with their burst; it isn't anything different from what you could see from a mage in Cata. The damage could be stopped, and it seems like they have to cast to kill something. If I stop the casts, I can keep my team alive. The burst can be very high, but at least they have to CAST.
3) Warrior mobility/damage seems a bit overkill. I do not like how warrior mobility seems to be based on how well they will stick to mages or hunters. This means classes like warlocks and priests are -never- getting distance from a half decent warrior. I'm not sure where the problem lies with warrior mobility design, but I think this has always been an issue. While I do agree that warriors need a lot of their current tools to put up any sort of fight against mage teams, I also think this mobility is too much against classes without mage-level control.
4) Defensive cooldowns seem grossly overpowered for certain classes or comps. I played several games against Druid/Mage/Spriest, and it was actually the most impossible thing to kill anything. I am by no means claiming we played perfectly, but one of the games I remember our team played extremely well, and it was still -IMPOSSIBLE- to get a kill. We had a swap to the Druid (no ironbark or trinket or ice block) with a full fear on the priest, full hex on the mage, dance/demon soul swap to druid with a Haunt, but he LIVED!
If you are going for a kill on the Druid, you have to go through: Resto Leap (no idea what this is called lol), Life Grip, Barkskin, Ironbark, ICE BLOCK (words cannot describe...), Tree Form, mage peels (over-the-top with dispel change), priest off-heals, and LIFE SWAP????????????????
Random Thought: I do not like the fact that Unbound Will VT Fears you when used against Shadowpriests. Ex: I am feared and I have Vamp Touch on me, so I pop Unbound Will. I now get VT feared for a few seconds and then eat another CC afterwards. I'm not sure if this is intended, because Unbound Will does remove all debuffs, but I don't think it should VT fear or UA silence you for using it.
This is just one example, but it seems like classes have way too many defensive cooldowns and instant CC effects right now. Instant CC has got to go if this dispel change is going to be permanent.
5) Healer Mana - Doesn't matter, except maybe against Warrior/BM Hunter type comps, simply due to the imbalanced damage they do. This is the first season of the expansion, being played in -full- gear since this is the Tournament Realm, and mana does not matter. -IF- a healer somehow manages to go oom, and isn't a priest (since they don't seem like a real class atm), all he has to do is run behind a pillar and drink while his partner(s) use one of the million available defensive cds or instant ccs and he will be fine.
I think healer mana needs to be re-evaluated or the only comps that exist will be comps that can 100-0 something in a few seconds, or comps that can CC a healer for a year.
6) Getting Kills - Feels a lot harder than it should be. It seems like the only things that end games right now, are broken cooldowns. Ex: Warrior damage with CDs up, BM Hunters unleashing a zoo (I don't even), etc. While I do think damage cooldowns + CC on a healer should be necessary to score a kill, I think it requires too much to get a kill right now. Survivability is simply too high.
7) The State of Affliction
Granted I have only played one night of MoP, the class feels more or less the same as it did in Cataclysm. I felt like I played the majority of the games well, and while not my best play, certainly well enough to get a feel for the class and arena in general.
Affliction damage, when taking current defensive cooldowns, healer cooldowns, and healer mana into account, is completely miserable. My dots were not critting for more than about 15-16k on 375-400k health pools. This is with FULL gear, gemmed and itemized pretty well (could be a tiny bit better I'm sure), and with Mastery reforged on every possible piece of gear. At level 85, my dots were critting for 8-10k on 140-150k health pools (this is also with haste reforge, not mastery). So essentially, our dots are doing about 70%~ more damage than they did at 85, and health pools are 150%~ larger than they were at 85. Additionally, every class has a lot more survivability and defensive cooldowns, including healers, and healers don't actually use mana.
As for the Affliction playstyle, Blizzard seems to be following the awesome trend of dumbing things down until warlocks don't actually have to do anything at all to put up full dots. Being able to Soulburn: Soul Swap full dots onto any target, 4 times (with glyph) in a row is... umm... what? In Cata, I thought warlocks were in a relatively good spot for getting dots up; Soul Swap had a 30 second cooldown, and you could use Fel Flame to refresh your UA. You still had to cast a significant amount to generate a high amount of pressure. Now, you don't actually ever have to cast to get your UAs up. In fact, I had a few games where I would pop Demon Soul and my on-use trinket, and Soulburn: Soul Swap dots on their -entire- team with 3 globals. I think this is a terrible direction for the class. Warlocks need to be required to cast a lot more, and their dots NEED to do significant damage. Malefic grasp spam with full dots during Demon Soul + on-use is good damage, but outside of that, Affliction is completely underwhelming.
TLDR: Unless something gets changed with healer mana, Affliction is going to need a significant amount of damage buffs to make the spec competitive. Should Affliction get the damage buffs that it needs, I also think Soulburn: Soul Swap needs to be either a) removed from the game or b ) redesigned.
I haven't had a chance to play around with Destruction or Demonology yet, so I am not going to make any comments on either of those specs. I have heard that they both do well, but I have a hard time believing Destro would do decently vs. any moderately coordinated 3s team. Getting a Chaos Bolt off at a crucial moment seems like it would be extremely difficult.
Thanks for reading, feel free to correct anything in my post. I just got MoP a few days ago, so I am not an expert by any means.