It occurred to me that Ulduar has managed a feat that I have long wanted in raid fights: mechanics that make the ranged DPS run all over the place, while ignoring the healers. And it's all due to the Wrath changes that made tanking much easier.
In Wrath, it's a lot easier for tanks to generate threat. This has made tanking 5-man instances much easier. Not everyone is happy with this development, citing that 5-mans have become about AoEing everything down, but I think that in general it's made it easier and more fun for tanks and less skilled players.
Because of the easier threat generation, the tanks have a large lead in threat over the dps. In Ulduar, this has allowed many fights to use "Runes of Power". These are area effects where anyone inside gets a boost to their damage. As Runes of Power appear and disappear on the map, the ranged DPS has to run from one Rune to another. In TBC and 1.0, these mechanics might not have been as useful, as DPS were more likely to push threat and steal aggro.
These Runes generally do nothing for healers, so healers are free to ignore them. But DPS has to keep them very much in mind if they want to do maximum damage.
Of course, there's a limit to how much you can do with Runes of Power, as you can't make them too important without leaving melee behind. Still, it's a pretty clever mechanic that takes advantage of the greater threat generation in order to make a more interesting fight, while sparing the healers.