The event was fun. Took about 45 mins to an hour to complete.
1 tip-- when you finally get to the Operation Gnomeregan quest (after doing the pre-quests) you might end up standing around for a bit of time around the helipad waiting for the quest guy to come back. He leads teams into the battle (you don't have to be in a party to finish it, just be there and kill stuff) as groups. He will give you instructions when he appears and you can turn in your letter. Once you turn in the letter given from the pre-quests (see video in my post above) you will wait up to 5 minutes for the battle to begin. From there, just kill stuff and follow the crowd.
Don't go INTO Gnomer tunnels when you get to that part or you might cause the event to crash - wait outside the tunnels and let the trogs come to you before going inside after. You will probably see players telling everyone to "wait outside, don't go in" and what they are doing is trying to make sure the event doesn't bug out.
It was a fun event