I think you are doing it wrong. I have no problems holding mobs on me with my warrior using hammer, my friend with dual axes has no problem, another guardian friend with GS also no problem hodling aggro. From my experience, mobs seem to stick to heavy armored classes, sometimes they spent great deal of time to chase me when I kite.
From ym experience, mobs will attack people attacking them in melee.
The aggro system has more in common with GW1 than any other MMO.
Except it has very, very little in common with GW1 at all. GW1's enemies had a strong tendency to go after whichever target was easiest to kill, and didn't seem particularly interested in who could res. GW2's enemies very frequently go after the hardest targets to kill (with some exceptions; different enemies definitely have different AI, though this is true in both games) or after the ressers. About the only thing they have in common is that they both weigh distance to target.
The only aspect of the enmity system that even remotely makes sense is the revive thing. Everything else is just unpolished and dumb. I don't care how you rationalize it, a player should not instantly grab hate after shooting a half dead mob once just because they are far away.