Plenty of people like the challenge, but not everyone has the ability or maybe even desire to be in a guild capable of tackling it right from the get-go.
It's always been our intent to offer new raid tiers in Cataclysm that are difficult to provide challenge to the raiding guilds, and then gradually allow older content to self-nerf as people gear up through VP, and then eventual literal nerfs to the content. That's something we've been communicating for some time.
Burning Crusade swung the pendulum one way, and Wrath of the Lich King swung it back too far the other. We're attempting to find that middle ground where there's still something brutally difficult for the cutting edge, but content gradually comes down until it's extremely accessible (ie PUGable) either simply through gear proliferation, or literal content difficulty nerfs.
There's always going to be two sides of the fence, some people want things more accessible for them and that's cool, we want it to be too, and some people think it should be difficult and always be that way because that's the way they had to do it. The fact of the matter is that as an MMO the end-game bar is constantly being raised, and progression content is in general not a place where we're going to purposefully gate prestige through difficulty. There are some exceptions of course, hard modes and unlockable bosses are purposefully there to be more difficult challenges, but as a whole our intent is to create a constantly moving ramp upward for Normal difficulty raids. That has to mean that the Normal raid content that was the hardest will one day be the easiest.
You will very likely see this same happen for Firelands when the raid tier above it is released.
I don't disagree with Blizz a lot, but this is something I openly disapprove of. Yes, I feel that people who were unable to experience T11 content be given the opportunity to, but nerfing the content like this, is not going to help those players. Yes, they will be able to experience the content, get geared, then want to try T12 content, but with the T11 Nerf, it would seem that the disparity in difficulty is going to be more significant to those Post Nerf. I think most people would simply prefer a new difficulty level.
In stead of doing nerfs across the board as a "new feature" for 4.2. Why not create a difficulty level that is a step below normal. You could make all these changes on the "Easy" setting. They could still experience the content. Still get the gear they need with the same amount of speed, but those who want to do normal-modes as they were originally designed, can.
It is just a bit disappointing that Blizzard stated in the beta, as well post launch though blue posts and Giant Ghostcrawler Blogs that Dungeons are Hard, and that they like the current design, and then follow that up with Nerfs Across the board for Heroics, and then months later, Nerfs across the Board to Normal Modes. These nerfs do not help players become better it helps players stay at the same level they currently are.
That is just my 2cp I can tell by the blue responses since these announced changes occurred, that they don't plan on allowing any feedback effect 4.2, which is disappointing, but meh, it is what it is.