I never raided much at all during the era of attunements but I got a brief taste of it during the last installment of attunements in early WotLK. I love the concept and it gives a sense of accomplishment when you finally unlock access to a new part of the game. When I talk about raid accessibility, I don't mean making the content easier or requiring no effort to arrive at a raid-ready state, but rather that anyone who wants to raid can prepare themselves and be viable for beginning the current tier of raiding. If MMOs can find and maintain that balance, I will be a happy gamer. You could even incorporate attunements into simply accessing different parts of the game world like perhaps tying it in with the explorer path.