Ok so this is what blizzard poster said: "The actual boss mechanics are pretty incredible, and there are a few surprises players can stumble across in the raid as well!"
This is something im afraid off. Usually when blizzard makes "suprises" they are incredible hard, random or just fuckd up. I really hope that the firelands raids arent as random as bwd/bot/four winds bosses. 10 mans are hard if its about luck.