They did it in FO3 and NV with Power Armor helmets and certain things that went over a NPC's mouth.
This does fix how the voice sounds, but ghouls are a very persecuted group. I don't think most of the NPC reactions (in the vanilla game) will be appropriate, unless of coarse the devs took the time to write alternative dialogue with ghoulification in mind, kinda like they should do with low INT PCs.
I'd welcome ghoulification in a survival mode (assuming there is a "hard" or survival mode).
I didn't read the whole thread, mostly due to personal laziness, so I apologize if this was already discussed.
Why aren't there any ghoul children?
Because most cases of ghoulifcation are of individuals prior to the war. Making most of them 200+ years old.
(with few exceptions.)
Well... Originally there was one, his name was http://fallout.wikia.com/wiki/Typhon; he was in Fallout 2. There are no ghoul children in Fallout 2, because no one could be a child could be and be old enough to experienced the singular event that made all the ghouls (yes, every single one of them) in the Fallout setting. It happened in Vault 12 during the war, and the place later became known as the Necropolis [city of the dead] because of its ghoulish populous.
When a new team took over, they rewrote whatever they had to, to explain new ghouls, and Bethesda has followed suit. So now Ghouls are inexplicably commonplace instead of a dying reminder of the war that spawned them. My guess about the absence of ghoul kids is that they would have to have the same immunity to the player, yet they resemble the targets that players are conditioned to shoot at.
*All Ghouls are supposed to be sterile ~unless Bethesda has changed that too. Typhon was normal before the war, and a ghoul (eventually) afterward.
It doesn't completely stop it from what I gather.
Ghoul kids would be awesome. Imagine how cunning they would be to survive.
I'm not entirely sure that being a ghoul would make you such a widespread outcast and target. At least going by FNV, there are a fair number of ghouls in the NCR army, and a few others working as civilians around New Vegas. No body freaks out on Beatrix, Raul or Keely for example. IIRC there are some ghoul hokers and bartenders in Gomorrah.
I could roll with ghoulification if 1) it was optional and irreversible and 2) actually made a difference to stats and maybe opened up some ghoul-only quests.
Maybe there are a couple of areas where the rads WILL kill you, unless you are a ghoul. Balanced by a couple communities where you WILL be shot on sight.
As far as all the NPC dialogue changes, most wouldn't need to be changed except for the couple of shoot-on-sight towns where everyone's dialogue changes to "ZOMG GHOUL KILLIT KILLIT!"
Even simpler, a couple of towns won't even let you in the gate, only dialogue from the guards is "Move along or die, you disgusting monster."