Without skin, they wouldn't sweat. They clearly aren't "rotting" in the corpse sense. They don't seem to be missing muscle mass... just skin. Without skin and changing bacterial flora, they wouldn't stink. They may have a smell to them, but a stink is pushing it. Given their ability to be nigh immortal barring catastrophic damage, they might not actually deteriorate at all as long as they are kept out of incredibly harsh environments. If I remember correctly, pre-Ghoul medical conditions continue, since the mutation seems to keep their biological pre-War "status quo."
Edit: we are told they have weaker strength from decayed muscle mass, but, with exception to ferals, I don't actually see any. Look at Raul and Carol! They are pre-War old and seem just fine... minus the skin. A Feral Ghoul seems to be able to beat you to death just as efficiently as a raider, if not more directly and without the curse words. Plus, they seem to run just as damn fast.
Once again, we have to deal with anime levels of description: we are told certain things but not given actual visual cues.
Edit edit: comparing stats, it would seem Ferals do more unarmed damage than Raiders. So.