With the removing of attunement for Black Temple and Hyjal coming in 2.4, there's been a lot of discussion. Most of the discussion has looked at it from the perspective of "Nerfing content so slower progressing guilds can get into it." That's not really an improper way of looking at it, but I'd like to present an alternate perspective.
Not a lot of people got to experience Naxxramas. It was a high-end instance that required many months of raiding (which most were unwilling or unable to put in) just to tackle the first couple bosses. If you didn't trudge through MC/BWL/AQ40, you probably didn't have much business being in Naxx. There wasn't much time for guilds to start, either; if your guild wasn't already raiding when Naxx was released, you probably wouldn't have people with the gear for Naxx by the time you got there.
TBC has made a lot of strides toward opening up endgame PVE content to more people. The first step was the reduction to 25 players instead of 40, which made gathering a group of people to go slay dragons a lot easier to pull off. Badges and Heroics were a great start as well; players without access to Karazhan (when Karazhan was a big deal) could still get themselves to an acceptable gear level via Heroics.
When Patch 2.3 released, a new gear trend emerged. Badge loot, as well as loot from a new 10man, was added that rivaled SSC/TK - and occasionally BT/Hyjal - drops in quality. This helped the guilds that hadn't already been making strides in BT and Hyjal to kinda "play catch up" and get through SSC/TK. The attunement made things kind of annoying, but it's easier to kill Kael with 25 people in full T5-quality gear than it is with only a handful.
Now, with Sunwell, they're taking a new step - one that I think has a lot of potential. According to Drysc in a post I can't find at the moment, there's a BT-quality badge vendor on Sunwell Isle somewhere. It has yet to appear on the PTR, which means if it does exist (and Drysc isn't just crazy), it's probably unlocked as part of the server event. This more or less means that once the hardcore raiding guilds have cleared the early content, it will become accessible to those farther behind in progression.
I honestly like this method, and if Blizzard can avoid the attunement problem (or lessen it) in the future, it will change endgame raiding from a linear progression to a more dynamic one. The best raiding guilds still get into the top-tier content first, but the average joe who wants to see the cool fights but has no chance of getting into one of those guilds is still able to catch up. Everyone gets to see the cool content.
Many hardcore raiders seem to take some sort of offense to this. "Why should these guys get in here for free when I had to put all this hard work?" I honestly think this results from a bad attitude toward raiding. I don't know about anyone else, but I raid because I enjoy the fights. I like going somewhere with 24 other people and coordinating to accomplish something. We're the best guild on the server because we kill everything first, and allowing other people to see the stuff we've already finished doesn't invalidate that.
Okay, so now they just kinda seem to be handing out gear to everyone just for showing up. Adding Badges of Justice to just about anything worth killing is an interesting move, and giving people S1/S2 gear for raid tokens is... kinda silly, especially since those pieces aren't particularly hard to get anyway. I discussed this a bit on Maintankadin:
Really, as more of this patch unfolds on the PTR, I'm starting to get the feeling it's designed to be the "Rush everyone through everything they haven't seen yet before WotLK hits" patch. They've taken a lot of flak over the past couple years about releasing Naxx so shortly before TBC, it seems like they might be trying to make everything accessible to everyone before then.
I'm not sure how I feel about that overall.