The What:

This mod simply adjusts the body part data of the Ghost People to require the maximum amount of damage (255% of base health) to cripple any limb, meaning they will die and get back up far more often, and you will have to actually spend time finishing off downed Ghost People to kill them for good rather than instantly obliterating them in 2-3 shots.

The Why:

Dead Money is fantastic, but the Ghost People have a problem once your character gets into the higher levels, even the ones that the DLC recommends you play it at (Level 20+), particularly if you use modded difficulties to increase damage: They die waaaayy too fucking quickly to even pose a challenge.

Now the root of this problem isn't related to their HP/Damage values, rather it's the scripts attached to the ghost people. They're coded to immediately die and explode a limb upon any limb being crippled, and the cripple threshold of their Head is always 75% of their total HP. This means that not only do ghost people have 25% LESS health than they actually should, the fact that it's so easy to cripple their heads with repeated shots in V.A.T.S. means that they will almost always have a limb explode before their health actually drops to 0.
This not only makes them extremely easy as long as you're using a weapon you're actually good with, it also means that they never get a chance to actually resurrect, which is THE PRIMARY MECHANIC THAT SETS THEM APART AND MAKES THEM UNIQUE AS AN ENEMY, and it never gets used or explored the entire game if your character is built properly.

It also removes all tension from what should otherwise be a spooky and extremely difficult part of a NV playthrough, because the gripping atmosphere the Sierra Madre is trying to convey gets shit on big hard when your character can 3 shot anybody with a revolver you can fit in a purse.

The How:

Simply download, extract, and enable the .esp. I would have liked to have found a simpler method for something that's editing, I think maybe 6 records in total? All of them the body parts held in NVDLC01GhostPeopleBodyPartData. This is the only thing this .esp overwrites, so this plugin is very mergeable, and in fact I recommend you go ahead and merge this to save yourself the increase to plugin limit. This mod is incompatible with any mod that alters NVDLC01GhostPeopleBodyPartData, which as far as I see don't exist, so it should be compatible with most rebalance mods. This mod requires nothing to run except for Dead Money, obviously.