Everything Boysea said about the murkglider lair was exactly the same experience we had. We also took every avalible left. Killing the PH's (the odd mob out) will either spawn a named or another PH. These did not spawn in the place the PH was killed but rather as a repop to an area we had already cleared or in further where we had not killed yet.
We killed for a few hours and got several rat PH's to spawn and the named rat. (a dark scuterrling or somesuch) We killed a few tatterwing bats but only got more of those to spawn and never a named bat so I never did figure out what happens when you do as the historian asks, hence completeing the mission.
Enchanter pacify works easily in here and the mobs were easier then a normal Ldon but with perhaps more HP. took awhile to kill each one even with our decent DPS but they don't hit that hard either. (max hit's were 600 or less on our pally) the named rat was no harder then any other mob but it did summon.
On a side note one of the people in our group was using a cheater program that shows all spawns in a zone. With our experience and that persons program i would have to say the murkglider lair is all about killing as many mobs as possible in order to get the named to spawn. So if you do not want to be here for hours on end bring ALOT of dps with you and kill as fast as you can. Again....this lair was easier then a "normal" Ldon and it gets boring very quickly.