I have reported this issue in-game also on several occasions, but lately I’ve been taking its existence for granted. There are some cases where respawn rates are bad-to-insane. Unfortunately, I don’t have memory of the exact area as I play different characters in different zones (and as I mentioned, I stopped keeping “scores”). For fast killing ultra-dps players or runners, this can be something not much of a visible factor.
Although I do remember 4 risen thralls (faced individually, all in the same area), not in Orr, that respawned BEFORE they died! One might ask how is that possible! I was fighting melee range, right in front of the mob, while its health replenished in full; and in one occasion, 3 times. They were no veteran nor champion. Just regular ones. That was the peak that made me feel thankful for some other mobs that respawned before I’m able to loot them (which are a considerable amount)! The fact I do clearly remember is that it was very late at night (or early in the morning) and the map was virtually empty.
To clarify, I didn’t move out of the mob’s area of “responsibility”. I attacked its spawn point and remained there. It’s health didn’t gradually increase. It just popped instantly back to full (similar case perhaps with an Ogre Champion Chieftain).
While in most cases the respawns have improved, there are still extremities.
Thank you for taking the time!