Well my guild HAT managed to actually defeat Yogg-Saron this past Sunday, April 19th. It was very challenging to defeat the last boss. Our melee dps had to squeak out every last little bit of dps on the brain below...
My roll as a feral druid went like this:
Phase 1: Gasseous clouds with adds spawning - Tank in my full feral dps gear and spec.
Tanking these was slightly tricky. The biggest thing I learned was to always go behind an oncoming cloud.. because if you try to beat the cloud, you end up halfway around the circle and could get out of range of heals, and it just slows the whole process down. Slowing processes down on this end boss is a bad idea. Other than that, we had melee dps stop attacking adds that got down to the 50 percent life mark, then proceded to drag the add into the center for range dps to finish off when it was next to the boss in the middle. We had 3 tanks picking up the adds, each of us would mark our specific add and "claim it". If we performed this first phase optimally with zero clouds producing extra adds (other than the very first cloud that we intentionally activate), we would have only 2-3 total adds left by the time the second phase dawned upon us. Oh.. yes, I also talked my lead tank into letting me zoom into the room in kitty dash mode to activate the first cloud.. which is rather fun!
Getting the optimal phase one took numerous attempts.
Phase 2.... DPS down the remaining adds and pull them away from the raid before they blow up on people. Then we focus fired down the small tentacles, (I switch to kitty mode from this point on)... and the other two tanks work on de-activating the large tentacles that the range DPS focus on. There is approximately a minute and 10-20 seconds from when this phase starts to when the portals to the brain appear. The key to this fight is having every single melee dps ready to take those portals as soon as they appear. Usually I was one of the last ones to enter because I have kitty speed, and let the slower ones in first knowing I can easily catch up once I enter. I hardly could get in enough hits to hit my Savage Roar, but I do get it in before: Fairy Fire the Brain, Feral Charge the Brain, DPS rotation the Brain, exit through the portal when the melee leader tells us when to exactly get out!
Don't pick a portal with a translucent brain tentacle over it... you can't click through the tentacles or waste extra seconds trying to click it....
Phase 3: Only took us 2 tries. (because our lead tank Katrina is insanely awesome). I would look for any non picked up adds and pull them toward the raid to dps down. Of course they hit like a freight train the moment you pick it up, so I hit all of my "don't die" buttons. The other two tanks kept the rest of the adds on them for the full duration of phase 3. The tanks never faced the brain to avoid excessive insanity and could tank for a prolonged period. My pick ups in the begining basically gave them both a chance to grab an add and fully charge their sanity and then get into position for full time tanking.
We got Yogg-Saron down with zero people going insane, and only one combat rez I believe...
I sat rather stunned once it was over. Usually we take more learning attempts to get down an end boss that what that took us. It was a lucky night for us, and we also got the Server first kill on that boss as well as several of the other bosses in Ulduar.
After Tuesday, the nerfs started... and we notice some significant nerfings of the medium mode bosses we managed to get down before Tuesday. We actually tried Council on Hard mode first, but it seemed getting the DPS to kill Steelbreaker (the huge dwarf) at the end was unreasonably demanding and probably impossible for us at this point before our tanks are destroyed.
I assume the other larger percentage of players who are able to complete Naxx.. even pug Naxx sucessfully... complained about finding "Easy mode" Ulduar to be "not so easy" and complained... And so.. thank goodness there are multiple levels of difficulty for the smaller percentage of players who are not drunk or drugged during our playing experience who enjoy the strategie and the challenges of HARD content.