So, near as I could tell from testing, the most major issue, is that on initial combat/aggro initiation on enemies and then applying stealth/invis/blindess:
1. The enemies will never stop even after swinging at your last location and repeat this until you can lose aggro entirely by being non-detected (stealth/invis) and then immediately at a distance that is much greater than what enemies can use to chase after you after taking a Dimension Door, otherwise, they will chase you down even to the start of a quest whilst each enemy swings at your last location and repeats it again and again. No amount of running at Superman or Flash speeds will ever let you lose aggro with the current version in play.
2. Or, enemies need to be able to occupy the same x y axis on a map and detect for you after swinging (and not hitting anything) and then you sitting tight until they lose aggro (easier with less enemies) - I am assuming this is the "player is dead" check as well to tell enemies to stop swinging. So long as you can (again) gain enough distance away from them then, you will no longer have aggro (but the distance needed is silly large to avoid enemies from retriggering). This obviously can't be done everywhere as the Devs specifically try to avoid having things for players to perch on to enable something like from happening.
3. But, so long as any enemy has your aggro still, group aggro mechanics means everyone will start up again periodically (and you are unable to lose aggro). This means normal Reapers will ruin everyones day immediately.
4. It also means that casters when facing a teleporting enemy that comes into the vincinity (and aggros on them first as they qualify now) can no longer rely on going/being Invisible and letting that enemy swing in the air. This is terrible for a multitude of reasons, since an Invisible Healer could spam heals in general safely, but once aggro'd the Healer will no longer be able to just concentrate on healing, but need to avoid the enemy as well if the rest of the party is not attentive enough to pull the enemy away from them.
So from that, we can tell that the missing part is for enemies to stop after a few attempts at tracing your last location and failing to get a result without magically knowing where you are even when you are quite far away (otherwise they will keep repeating with no end to it). (Point 1)
I literally dragged ALL the "blinded" enemies from A Sharn Welcome from the Bear room all the way back to the start, and only using DD after going invis stopped the aggro; otherwise each "blinded" enemy will just keep running to your last location and keep doing so until they have swung at your present location (x y axis on map) at least once before they drop aggro. (Point 2)
So the satisfaction (in code) that they have checked that you're no longer there is not being fulfilled currently. (Point 1 and 2) I am assuming once that is put in, this should work more as intended.
I would request that this not be deployed to Live servers yet (especially in its current incarnation), as we have no idea if the changes made for the next iteration will cause other uninteded results. Unless if the Devs would like me to deploy 24 characters each Purple Alerting a Dungeon and then retreating to safety to cause server performance issues for everyone, because - you know I would be happy to do that (for science!).
J1NG