Halfus Wyrmbreaker - Bastion of Twilight
Due to a plethora of horde loitering around the Blackwing Descent stone, we went over to the Bastion of Twilight first to test out Halfus Wyrmbreaker.
Firstly - when zoning in, there is a lot of trash. Many cries of 'oh no, it's Tempest Keep all over again...'. You WILL be using CC and you likely will spend a little bit of time negotiating this first hall of trash (though it's subject to change come release, of course). I think we had two saps and two sheeps up on every pull. We went through it pretty quickly to get to the boss so I don't have detailed descriptions of all the trash adds in there. Some do hit fairly hard though. There are also mobs of blood elves on either side of the first hall standing around light balls of energy - the blood elves don't hit very hard so these packs you can manage to just pull at once and AOE down. You will need to kill them, though, as the orbs they surround will channel a harmful beam onto you if you don't kill them.
When you go into his room, you will see him standing at the edge by a proto-drake. There's a Slate dragon injured laying to one side, a Storm dragon chained and a Time Warden (Bronze dragon) chained. For basic abilities - the proto-drake fires large Fireballs at raid members, they are pretty easy to see coming towards you. The boss doesn't hit too hard, though he does do a cast which, if not interrupted (and it did seem to be interruptable), will do some AOE damage to everyone and knock everyone back.
You can speak to the chained drakes - however, at least as we did the fight, speaking to them released them, only to have them immediately mind controlled by the boss. The Storm dragon was really quite bad to free - he does some decent sized hits, but also creates an aura which interrupts casting. Consequently, all our healers kept getting interrupted. This does seem to interrupt the boss as well and helps mitigate his AOE cast, but it was very difficult on the healers. The Time Warden drake was a bit better - the debuff he put out froze us all in place, so we were unable to move (and so unable to be knocked back by the AOE from the boss, which was helpful).
What we ended up doing was engaging the boss, then the second tank and melee heading over to the Time Warden. We freed him, were locked in place, then nuked down the Time Warden. Once he was dead we returned to the boss.
When the boss got to ~15-20% or so health, he began whirlwinding around the room (BOOOONNEESTTOORRMM). He is tauntable, and didn't appear to go taunt immune, so our tanks were able to help martial him into place. As is probably obvious, don't stand in the whirlwind.
Healing impressions: The damage was a bit mixed on this fight. Tanks will be taking damage and the raid will be taking damage from both the fireballs and from the AOE the boss does. That AOE cast does appear interruptable, so everyone who can interrupt it should be trying to do so. Mana and mana management is definitely going to be big in Cata - all of our healers were running low. I was having to think a lot more about which heals I could use, trying to use Regrowth or another expensive spell on Omen of Clarity procs, and being careful not to waste heals with overheals. With healthpools at such a large size, it doesn't seem tanks will be dying within a GCD (not yet, at least), but you definitely will still be healing and they will die. You may also have to let your raid know what they can stand in - as you can see in the screenshot below, Efflorescence makes a nice green zone. Shamans have an AOE heal that makes a blue circle, and priests have one which makes a white circle.
Omnitron Defense System - Blackwing Descent
Second up was the Omnitron Defense System over at Blackwing Descent. This was a pretty interesting fight, and also seemed a bit easier than Halfus Wyrmbreaker.
There are four golems in this, but only two will be active at any one time. They all share the same health pool. They do not seem to do any cleaves, but there is some directional damage to be aware of which I'll get to. Only one golem will be active when you approach. The golem has 100 energy stored up - when it gets to 50, another golem will charge up and join the fight. Once the first golem gets to 0 energy, the next golem will charge up and join the fight, and they will rotate until their shared healthpool is gone. There is an obvious stream from the forge in the back of the room channeling to a specific golem, so it is easy to see which golem will be activated next.
Bosses: (abilities sourced from wowcataclysm-wiki.com)
Incineration Security Measure: Jets of flame fire out all over the room. Don't stand in the fire, and the tank shouldn't move or rotate the boss.
Acquiring Target: Targets a raid member and, after a few seconds, shoots a jet of flame straight at them. Rest of the raid should move out of the way, and the target needs to be healed.
Barrier: Absorbs 300k damage and explodes to deal 75k damage to everyone. Do NOT attack the barrier.
Lightning Conductor: Puts a debuff on a target that hits nearby raid members. Healer or DPS should move away from the group if targeted, if it's on the tank, tank should remain still and DPS move away from the tank.
Chain Lightning: Deals chain lightning - the raid should remain spread out.
Unstable Shield: When struck, the boss lets out a very high AOE damage. Do NOT hit the boss when the shield is up.
Poison Cloud: Causes anyone standing in it to gain a debuff that increases all damage taken by 50%, including the boss.
Poison Protocol: Summons 3 slow moving slimes that crawl towards a chosen target. Ranged DPS should kill the slimes. If the slimes reach their target, they explode for ~100k and leave a pool of poison. Don't stand in poison and don't get hit by a slime - kite it if it targets you.
Poison Soaked Shell: The boss puts a stacking dot on the attacker when struck. The dot does give a burst of nature damage for the attacker (10k per stack), however, it will deal damage to you as well, so don't stack it too high.
Whirlpool: Gives anyone standing in it a boost to damage and mana regen - stand in the whirlpool but ensure the boss is not in it.
Arcane Annihilator: Short, interruptable cast, does a lot of damage to one target. Buffed by Power Conversion.
Power Conversion: The boss generates a stacking damage buff whenever he is struck. Do NOT hit him with this up. The damage buff is apparently spellstealable.
The biggest consistent thing for each of the golems is they put up some form of a barrier or shield which, for the most part, will result in massive damage to the raid if they are struck with it up. Quick target switches will be key in this fight.
Healing Impressions: Healing wasn't too bad in this fight, and a lot of the raid damage can be avoidable. The most precarious moments were when someone DPSd one of the golems with a barrier up, which resulted in the entire raid taking a massive drop in health. So long as people move out of fire, fire beams, poison, etc, and are quick on their target switches, healing will not be too bad. I can easily see people wiping a raid though by missing a target swap when one of those shields is up. Again, mana management will still be important, and your raid will need to help healers out by, well, not standing in bad stuff. This was a pretty fun fight though.
The instances themselves look pretty cool, certainly the zones and architecture/graphics inside look pretty amazing. The first hall in Bastion of Twilight will be... uncomfortable... for some, mainly due to the intensity of the trash in that first wing, especially as the first few pulls are in a fairly tight corridor. There's always the potential that may change between now and Cata, of course. There wasn't too much trash that we saw approaching the Omnitron Defense System in Blackwing Descent, though, just a couple of golems. They did have a targeted ability which did some heavy aoe damage, but it's pretty obvious (another 'don't stand in bad stuff' ability).
The DPS also got to have some fun with essentially a giant DPS dummy, they spawned a Patchwerk for us:
Overall Healing Impressions:
Mana management will definitely be important, especially in the first tiers of raiding.
For these tests, I used the following spec:
I used this spec to try to maximise what I could healing-wise in the Resto tree as well as maxing out Genesis in Balance. Blessing of the Grove still feels a bit weak, especially at only one point (2% boost to Rejuv instead of 4% at 2/2), so I put my spare point into Furor instead to just increase my mana pool that little bit more. Nature's Grace has been improved fortunately for Restoration druids, the haste boost now procs off of Regrowth as well as off of Moonfire and Insect Swarm. The wowtal calculator isn't updated to reflect that change yet. The most recent beta patch also made a great change to Empowered Touch which causes both Nourish and Healing Touch to refresh Lifebloom stacks. Unfortunately, this talent is currently bugged on the beta and neither spell is refreshing the stacks, but hopefully that will be fixed soon.
Druids are still excellent at raid healing and our HoTs are still excellent. The Rejuv durations are shorter but you will definitely be using them. Mostly instead of pre-HoTing everything, you'll be healing a lot more reactively, as overheals will end up wasting a ton of mana. Regrowth is a bit of a tricky spell at the moment - it's a very quick heal which is great, but it costs a lot of mana. Nourish and Healing Touch cast times both feel a bit long, but I think this only felt a bit worse because of the current bug to Empowered Touch, as I was having to constantly refresh my Lifebloom stack on the tank in between my other heals since the talented refresh isn't work.
The longer cooldown on Wild Growth really isn't a problem - it's still an excellent AOE heal and you will be using it (and it too can crit, which is great). Because of the longer cooldown, though, you will want to be very careful with how you target it - if you throw your WG onto a bad target so it ends up hitting just one or two people, that really ends up being a huge waste of both time and mana. Similarly, you will want to be using your swiftmends as an emergency heal, but be very aware of where it's landing to try to make best use of that Efflorescence proc. On beta, at least, the graphic is showing up (there seems to be a projected textures bug on live at the moment where abilities like Efflorescence, Consecrate, etc aren't showing up in some places), so once your raid realises that it's a green zone they CAN stand in safely, they'll move into it. You will want to target it most of the time though to maximise its effectiveness.
Tree of Life form too is a good cooldown to use. Being able to throw Lifeblooms on multiple targets will be very helpful (particularly on tanks on fights which have more than one taking damage), the additional Wild Growth will really need to be targeted well, and the instant regrowths are very useful for quick top-ups (just be careful you don't spam yourself OoM). I must say as well - Tree-Wrathing is pretty awesome and fun. Tree-dps (or TreePS as I like to call it) has gone up a fair bit, now that we have access to crittable Insect Swarm as well as Moonfire, plus very quick and harder-hitting Wraths. You likely won't be able to do this in raids until you overpower the fight (or just if the mechanics call for it) but it's a lot of fun particularly in randoms and things. I'm still undecided about the new tree form as well, I just might go for the new glyph to keep my little treant form.
That's all for now, I'll try to update with better/official information on Halfus Wyrmbreaker, and if our run's videos are posted I'll include a link to that as well. Tankspot does seem to have a couple of 10-man videos of the encounters posted so that can give you a glimpse as well.
I'll leave you with this lovely screenshot over Searing Gorge.