Deathwing? In dragon formIt's only open for 1 week at a time. Most people would not have the capability and/or patience to even clear trash if they scaled dmg to actual tBC numbers. Game is way too different today than what it was back then.
Did it myself with the guild, trash was easily the biggest pain. Soo many of them with crazy spike dmg or annoying CCs. Beyond that, we only wiped to Reliquary and Illidan. Thankfully our raid leader was very knowledgeable on the boss fights, I went there completely blind.
Also, is there a boss bigger than Supremus? Sweet mother of titans that guy was huge!