and here's the thing. For people like you, the Vanilla/TBC model works fine. To use TBC as an example, one day you'd do Kara, and another day you'd progress in SSC/TK. By the end of the xpack you'd probably be somewhere close to killing Illidan. Nothing got fixed for players like you when multiple difficulty settings were introduced.
It was only the people who wanted to do zero organizing, no preparation and basically just log in, mash a button and wait for the lore to hit them in the face. So while I would call you a pretty casual player, you're not 'casual' in the derogatory sense. You just don't play that often which is fine. You aren't part of the problem.