The thing is just about the resources, warriors need to build rage in order to get aggro from their rage consuming abilities. Sins ans BHs have a resource that is already "full" and can use almost all their abilities from the start and thus create fast aggro. DPS seems to do the same thing, if the fight starts they blow all their big resource consuming abilities to do as much dmg in the start to end the fight as fast as possible. But this isnt how non warrior resources are designed, the more resources you have the faster it regenerates and thus have a more steady stream of dmg. As the game gets older people will learn how to dmg and not go at it wow style and thus making it easier to keep aggro. Im a lvl 24 jugg now and have done quite some flashpoints already and i only noticed that i had real troubles with aggro is when there is some dps that thinks he needs to use alle his resources in 2 seconds after the pull. Keeping aggro from healers isnt really a problem, just guard them and your fine.