It's not shitty game design any more than any other MMO has shitty game design. This shittiness is precieved by the industry to be a requirement to keep people playing/addicted.Slightly less shitty game design is still shitty game design.
The game's clientele has aged and many of its players have busier lives than when they started playing. That much is for sure. SE has accommodated that to some degree. I'm sure even at the very first day of the game's launch, everyone would be totally happy if there was no wait time for anything whatsoever. But some wait times are necessary or your players tire of playing too quickly and you lose your player base (and therefore $$$)
Think about it- if every several minute and day-long delay was removed from the game, we would have all accomplished our current accomplishments a long time ago. We'd have beaten each piece of new content in a fraction of the time it originally took, and we'd be a lot more bored now than we would have been otherwise.
I'm not necessarily suggesting that this is a good thing, because everyone loves having more time in their lives, but that it's essentially a part of MMOs. Every MMO has things you can only do once every so often, in order to gate and pace progress.