Tobold made a post today about how Blizzard could go about fixing the queue times for dps in WOW. His idea is that in a 25 man raid instead of having 5 healers, 2 tanks, and 18 dps there could be 23 dps, 1 healer, and 1 tank. This is a nice theory and all but it ignores the fundamental problem - people are willing to wait 30 minutes to queue as dps. That means that if you do things to incentivize people playing tanks and healers or make less tanks and healers necessary you will still see people signing up to dps with a 30 minute queue. There isn't much you can do when a big chunk of the population would rather wait 30 mins than tank. You can perhaps increase the number of raids that go out, which is nice, but you won't change the queue time.
This solution also has the problem that it makes absolutely no sense. Without tanks swaps or multiple tank roles tanking has to be dead simple... and boring. With only one healer who presumably takes a number of spells to get a single person from nearly dead to full nothing can do any significant damage. If the whole raid lost half their health, the healer probably wouldn't be able to heal it up during the course of the entire fight! A single healer is so ineffectual that you might as well not even have one and just let the dps who stand in fire for minutes at a time die. In order for the current model of the game to work at all there must be multiple healers and multiple tanks and I can't see how completely redoing the entire game design just to alter the ratios in Looking For Raid is sensible.
If somehow we could have 1/3 tanks, 1/3 healers, and 1/3 dps it would be better. Then if a single tank or healer is totally useless it doesn't matter and you just keep on going anyway. The pressure isn't there anymore. Unfortunately that is terrible raid design so the players would try to get around it and run more dps, and the spec spread in the game wouldn't support it anyway.
People want to dps and they especially want the lack of responsibility that doing so entails. They are willing to wait 30 minutes in line to do that. There isn't a whole lot we can do to fix the problem. It is much like building a new freeway to provide better access into a city - traffic just increases to choke the new road as much as the old ones because if traffic improves, more people drive and any gains are lost.
The dps queue is 30 minutes and that is just the way it is going to be.