... if you are a damage dealer, that is. Leveling my latest character in World of Warcraft, a druid, is an eye-opening experience how much the favor has shifted in the direction of tanks and healers. It used to be that you had a choice of either playing a damage dealer, who would level faster through soloing, but have problems later to get raid spots, or playing a tank or healer, who leveled much slower, but could get into a group easier. Then Blizzard made leveling easier for tanks and healers, strengthening their soloing powers, and making it easier to temporarily switch to a damage dealing role for solo content.
The Dungeon Finder introduced another major shift in favor of tanks and healers, because suddenly leveling through dungeons is faster and more efficient than leveling through quests. XP per hour are superior in a dungeon, especially so if you have rest xp bonus left. And the item rewards from dungeons are far superior to the item rewards from quests.
But only tanks and healers get the full benefit of these Dungeon Finder advantages for leveling, because for them the queue time is reasonably short. They get the choice how they want to level, by solo questing or by group dungeons. Damage dealers get a much diminished version of that choice: They can't choose to exclusively level by dungeons, as the long queue waiting time for dps would make that unfeasible. They only have the choice to either exclusively solo like they did before, or to sprinkle a dungeon here and there into the mix, doing quests while waiting 20+ minutes in the queue.
Over time this new situation will maybe answer one interesting question: Why do far more than 60% of players prefer damage dealing classes, or damage dealing roles for hybrid classes? Some people say that this is inherent, that dealing damage "feels more heroic" than withstanding damage or healing it. Others say that most people are anti-social, and would rather solo, for which a damage dealing class is still the optimal choice. But there is also a theory that the famous "tank/healer shortage" is caused by the incentives having favored damage dealers in the past, that people simply drifted towards the classes and roles that leveled the fastest. That theory is given some credence by the fact that patches and nerfs which change the relative power of classes always result in the nerfed classes becoming less popular and the new best damage dealers becoming the flavor of the month. So if tanks and damage dealers are now the fastest levelers, maybe the tank/healer shortage will end, and players will create more tanks and healers as new characters in Cataclysm. That would balance out the situation, as with increased numbers of tanks and healers the queue time for damage dealers would decrease. Lets hope and see.