But sometimes you can get healing aggro because you have to overheal because the tank has to do a lot of extra job, or even give his back to another mob, getting more damage, or change target priority for a second because a dps is doing whatever he/she wants, and the other one keeps doing full damage without giving the tank some space to breath and fix all the stuff thus losing aggro on one or more mobs (keep in mind that the GCD is what is it, and a tank can't do an infinite number of actions at any given time). What I mean is that aggro management is a must for everyone in the party, be it for the tank to keep an eye on all targets and mark them, for dps to not go crazy and be able to slow down a bit, or for healers to not spam Medica, for example. Everyone would benefit the same, as enmity management is a responsability of the whole group, and it's mechanics are all intertwined.