, one of the premier guild ranking and data sites for WoW
raiding, reports that 1,000 guilds have defeated
the heroic Ragnaros encounter in Firelands. This number represents 2% of the entire pool of active raiding guilds, as well as 4.2% of the guilds that are raiding heroic Firelands content. If that doesn't put things into perspective for you with regard to Blizzard's trying to make raiding more accessible, I don't know what will.
Interestingly, 76% of the heroic Ragnaros kills have been completed in 10-man raids, with 24% of the kills in 25-man groups. Ten-man raiding has certainly made endgame raiding significantly more accessible, and 25-man only guilds seem to be struggling to keep their numbers as high as they once were, especially when the 10-man versions of the encounters are more accessible.