Attunements is a big deal to most people. Some love seeing attunements--I'm one of them. Others feel that all content should be accessible by everyone, as long the required level and gear is there. It can be discussed endlessly, so I won't go into my arguments as to why I feel attunements is a good thing.
The subject of attunement comes up all the time. We're researching design and technical options for the future when it comes to attunements. For example, we'd love it if once you earned your Karazhan Key or Heroic Keys, your max level alts had access to those areas as well. If we had the ability to do this, we probably would have left Heroic attunement at Revered rather than Honored.
We're also exploring the concept of guild or raid attunements as well. No promises here. There are many hurdles that need to be overcome before we'd be able to implement these (design and technical limitations).
We're very interested in doing more dynamic server events to open up content as well. The Sunwell Barriers are a good example of this, or the AQ War (only replace the massive collections with a series of cool, fun daily quests).
I can't make any promises for Lich King, as we are still undecided. But the topic of attunement comes up all the time here. We want to do a better job and are currently exploring the options.