There should not be any other races to choose from, because no one would want to play as something like a ghoul ( im taking the example from Gabriel77Dan) and have all these negative effects in trade from rad protection and so on. If there was diifferent races then they couldnt be affected so dramaticly.
If they aren't gonna follow lore then there is no reason to add them as playable races let alone have them in the game what so ever.
Ghouls are (originally meant to be) weak, their bodies is in a costant rot and regen state with some ghouls even having limbs falling off.
They aren't suppose to be as healthy or resiliant as humans when it comes to damage.
Their muscles are in this constant rot'n'regen, their running speed should not be the same as that of humans and they shold not be able to carry as much as humans would nor should they be able to wield Strength 8+ weapons or Heavy Armor.
But what do they get for this?
Poison and radiation
immunity, they get more skill points per level, better Tag's, get bonuses from eating irradiated stuff and being in irradiated areas whereas humans have to use drugs which have addiction and withdrawal negatives. They can't be detected by heat cam's, are allied with all feral ghouls and could possibly take a feral ghoul, that has taken a liking to you, and have him/her as a minor follower.
Hell, they could have a special ability called Faint Death, in which they lie down on the ground and pretend to be dead, fooling any human, trog or ghoul NPC's.
Ghouls are not Rambo or Arnold.
They are weak, but what they lack in combat efficiency they make up for in other aspects.
If they are just gonna be humans +1 then why bother implementing them at all?
They have to follow lore.