Since all ghouls look the same in Fallout 3 and NV, here are a couple of ghouls showing what they should really look like if the engine had the ability.
http://images4.wikia.nocookie.net/__cb20101028051910/fallout/images/4/40/FO01_NPC_Set_N.png
http://videolamer.com/wordpress/wp-content/uploads/2009/04/npc2.jpg
I'd say the engine has the ability to render anything in Fallout 1 or 2 as full figure realtime creatures (the model designs don't make much difference) ~ but.... lip syncing the ghouls would, since every talking creature (besides robots) uses the face-gen heads.
I would have greatly preferred they had made ghouls as creatures and not used the standard human assets. They did this with Ferals, but you notice Ferals never interact with chairs or clothing or weapons, and don't speak. They could have done them as Set and the rest were (as ghouls should have been done), but Gob, for instance, would have taken more work to create, and (I think) have been seen by some as reinventing the wheel.