How does aggro work?

For instance, is there any way to keep mobs from ganging up on healers in PvE? It seems to happen with almost every type of mob I've faced (not just a couple types as some have said), and there doesn't seem to be a dang thing I can do about it unless I'm a tank that can step in or a healer that can keep the other healer alive. No matter how much damage I pump at them, they usually stay fixated on the healer once they've started in on her.

Other MMO's I've played have had recognizable and predictable aggro rules that I learned with little trouble and could use in employing tactics. So far the aggro rules in GW still confound me. Whether that's because they simply don't exist in the form I'm looking for or because they lie deeper than I'm looking, I don't know. Given that GW seems in most respects simpler and shallower than other MMO's I've played, I'm inclined to think it's the former. Does anyone have a good handle on exactly how aggro works?

On a side-note, I've noticed that escort missions are distinctly harder when the only healer is an NPC; the NPC healer's AI never seems to take the escortee into account.

I noticed most mobs will jump at healer and caster in a team automatically no matter who pulls. Typically healers will just need to run couple steps or a half-circle, then mobs will stop to attack others.

I played DAoC for a long time and that promotes teamwork and agro control to the extreme, which I really like. Most casters are two-shot die, so there is a whole system on who pulls who agros who tank 3rd incoming mob etc. So when I started EQ2, I felt their combat system and teamwork is so amateur. Same as GW

It seems that the mobs will go after the weakest in the group (I think this has been said specifically before) so that's the Mage and the Healer. But as a tank, I have some experience trying to deter them from this, and it seems like you really need to use the fact that you're a solid object in this game and enemies can't pass you. If you can get right in front of an enemy and get a hit in before they run by, then usually him and any closeby friends will attack you instead of the healer/mage they were running after before.

Most aggro in games go by a "hatelist" and whoever has done the most damage is the highest at their list. Also things like healing and whatnot can bump up your name on the hatelist. That, IMO is very primative way to do aggro. To be honest with you, I think the enemies aggro in this game is actually a little more complex.

Hm, that's a good point (that GW aggro may actually be more complex). I'm so used to hatelist style aggro (alot of EQ1 back in the day, WoW more recently). Going for the healer first is usually the smart move tactically, so that could be a sign of better AI instead of lesser. I'm used to dumping damage on something to get it's attention, but that doesn't seem to work very often in GW. I should have guessed from the lack of taunts and evasions that the aggro wasn't at all hatelist oriented. I'm not used to enemy AI mirroring mine so closely. Of course, they have significant lapses like not moving out of AoE spells; I guess I saw things like that and assumed the enemy AI was of the dumber variety.

Most AEDoT in GW are ground targeted instead of point blank. so if mobs are smart enough to move out of my fire storm area, I'll reroll a necro today.

I find that it really depends on what type the mob is. They all seem to have different attack plans on who to go for.

I am a Me/N and I find that mobs GO RIGHT FOR ME, especially if I am holding something like a seed or something. Makes sense because a caster can shut them down basically. If I can tie the mob around a few warriors I can Echo a Mesmer skill and cause MASS damage on them from their attacks.

I can get out of the mob by running a circle or going thru some warriors so they block them from me

I honestly stay a good 30 yards back out of their range, let the warriors engage and let the enemy swarm them. Once they're going at it with the warriors full force I'll move in and start nuking. I'm E/Mo.

As a monk player, i can tell you that attempting to put a warrior between you and an aggroing enemy will usually make him break off