First of all, this instance launching thing has been going on since well before the patch, so blaming all the casual players is misguided, although I'm sure that didn't help the problem. Why on earth Blizz would implement something that would only encourage dungeon crawling when the system was already broken is the height of stupidity.

Second, it's not just a "few minutes" trying to get into an instance. Try thirty minutes minimum. I have several nights where my group received the "instance cannot be launched" message for an hour to an hour and a half before we finally gave up in disgust. For someone who only has a limited amount of time at night to play, that's an unreasonable amount of time invested in waiting to play. It doesn't seem to matter what time a group tries to get into a dungeon, either: my husband tried to get into MC at 2am and it still refused to launch. Oh wait, that's right, MC is an old-world instance; trying to get into one of those or even BC dungeon is impossible.

I, for one, have never been so happy to see an extended maintenance on Zul'Jin since I started playing 2 years ago.