When Cataclysm was being developed, Blizzard announced a lot of changes that they would be making to the raiding scene. Specifically, 10- and 25-man raids would now essentially be considered one and the same. They would share the same lockout, reward the same loot, and generally be considered as equal.
The community, in their grand resistance to change, called foul on many of these changes. Certainly, WotLK created an embitterment towards 10-man raiding as being "easier" or a "lower class" of raiding that simply wasn't on the same scope as 25-man raiding. In their defense, they had every right to think this because that is exactly how Blizzard had made raids at the time.
Now that we've been through a whole tier of raiding under these changes, and as we move onto the next tier, it is time to reflect back on all of the arguments that sprouted and see how realistic they really were.