[blizzard]During the scheduled server maintenance on the week of January 31, the Dragon Soul raid will become enveloped by the "Power of the Aspects" spell, reducing the health and damage dealt of all enemies in the raid by 5%. This spell will grow progressively stronger over time to reduce the difficulty and make the encounters more accessible. The spell will affect both normal and Heroic difficulties, but it will not affect the Looking for Raid difficulty.
The spell can also be disabled by talking to Lord Afrasastrasz at the beginning of Dragon Soul, if a raid wishes to attempt the encounters without the aid of the Dragon Aspects.[/blizzard]
Source (http://www.mmo-champion.com/content/2623-Dragon-Soul-Difficulty-Changes-Curse-Weekly-Roundup).
DS buff going to 15% next week. I think at that point DS will officially be easier than Firelands.