Just a random thought, but sometimes it seems like it is a lot harder these days to schedule things, to get people to commit to showing up at a given time in advance. Not just in WoW, but in real life too.
I wonder if it is related to the increasing inter-connectedness of our social lives. Sometimes it seems that everyone wants to leave their options open. To not commit to X, because there's a small chance that something else more interesting might pop up in the time between now and X. And because of the speed of communication, you might hear about the new thing in plenty of time to go to it.
It just seems like in the past, because it was harder to communicate with people, that people ended up making arrangements earlier, and sticking to the arrangements with more faithfulness.
I'm not really sure which way is better. Ad hoc gives the individual a lot more leeway with what they want to do. But it does make life a lot harder on the people who have to organize events.
And I think there is a strength in scheduling that is often undervalued. To be able to count on people to show up when they say they will show up. I've always felt that the single greatest characteristic I would want in a raider is dependability, not raw skill.