I've been so busy at work and home recently that I haven't had a chance to really look at this event. Obviously as I have my Proto Drake now I haven't had the motivation either.
But last night I saw a request in trade to go do the event boss so I looked at the achievements panel to find out what it was.
Well, it looks like they have completely redone the meta as well as the general look of the event as you wander around Stormwind or wherever.
I am sure they have added new achievements to the meta, or changed existing ones, as I completed the event last year you'd hope they wouldn't remove your meta-achievement if they changed the requirements this year. Don't fret they don't. I looked at my achievements and they are all set to complete even though I definitely don't recognise some of them.
The new boss(es) is(are) in Shadowfang Keep. I'm pretty sure it was THE ICE STONE IS MELTING* in one of the TBC naga instances last year. TO be able to summon them you need to do a few quests in Stormwind starting with the goblin outside the bank. Take some samples from guards, go do a timed run in goblin disguise to the city gates, speak to girl in Inn, go looking for Goblin in bank, AH and barbers and finally down to the docks.
*EDIT: According to Red in the comments The ice stone was Midsummer Festival. I had an inkling it was a different event and that makes sense. I think the event used to end with your trip to the dude near the rogue camp in Hillsbrad.
Then you'll get the quest to talk to another goblin in SFK. Get a group go to SFK, summon 5 times and do a pretty hard fight. Key: DON'T STAND IN THE FIRE!!!!
Well, whilst doing the prequests for SFK event boos I had EvilBastard leeching a Heroic FoS run. Evil is as Evil does. I would have him on follow sometimes, get to a boss, throw out a rain of fire and then swich back to HW to carry on running round SW. He died a few times. But for the first time ever I saw the battered hilt drop. I rolled 34. LOL. It was won on a 98 I think.