It's well established that destroying the brain is a valid method for killing zombies. It's fine if it doesn't work on skeletons, they don't have a brain.
I can decap gelatinous oozes on my berserker, so yea you should be able to headshot a mob with a.. head.
Rangers get to experience what playing a paladin is like?! Niche abilities (almost) completely unavailable for an entire expansion?!
Headshot never really worked in current expansions unless there was some mecca of headshottable mobs in TBL that I wasn't aware of. 115 should open up a lot of ROS's sarnaks.
It's not just a TWD thing. Since you're apparently new to zombie fiction, it's a very common trope that destroying the head destroys the zombie. The Rivervale monster mission, Brraaaaainss, even contains the halflings shouting to "Hit them in the head with a stick!" which implies that it's a valid and well known strategy in Norrath for zombie disposal. Further, the quest text and npc names imply that the npcs infected with the living ice aren't quite dead and aren't quite alive either - some of the orcs are billed as "an infected orc" which implies that there's a potential for recovery.
Paladins get this expac (and a few limited cases in others). Rangers get for the most part, 19 years of EQ. The devs never got past the guilt of screwing you in the early days (especially with LoTR movies giving rangers so much positive PR at the time) so you will ALWAYS be awesome most of the time. If not ALL the time.
So there is some zone with an abundance of these mobs in TBL? The only thing I can think of that is below 110 in PoF is maybe a jopal or two. I didn't do a whole bunch in TBL though. In ROS, there were a few Sarnaks in Overthere, but not a whole lot and it required a lot of traveling to get to them since they weren't bunched. It was not worth the effort. EoK was pretty sweet. Yeah, there was always a spot to level a ranger in no matter how tedious.