It's clear the devs, some time ago, decided that in order to expand the player base and keep the game moving forward was too supremely orient the game toward the Casual Player...in terms of the casual being able to gear up as well. So they blended tier/emblem systems, so they allowed t6-equiv gear to be obtained at SSO badge vendor. I guess they figured that it would take the true Casual Player a good amount of time to build up the badges for that and yes, at this point, I would also argue that for said true Casual Player, the current tier gear available at the vendor(s) would still take quite some time to build up.
Yet the game's clearly not just Casual-Hardcore. There are more distinctions. There's the 'casual' who does still farm heroics but doesn't raid often, or pugs raids infrequently. That's just one.
As for making most of the game obsolete...that's why they introduced the achievement system. Personally I think it's hogwash. Hugely smart on Blizz's account, as they saw many people skipping out on content and it made them all Faklempt that some of their work was for naught. I however don't go out of my way for particular achievements (for the most part), but I'll still try for a clean Heigan and if I'm bored, waiting for the rest of my group to get to UP, I"ll fly around Howling Fjord and get the exploring achievement. Yes, the achievements won't/don't fully satisfy, but WoW's--in my experience--full of 'Gimme' capitalist-type people always wanting fresh content, new things. Yep, Blizz could expand and work 202309230834 x faster/harder, but I do think they realize the demand for things So Fresh and So Clean (a la Big Boi) and are working frantically to bring it.
Edited, Apr 10th 2009 8:43am by frugalmaelstrom