Khabib is a horrible weight cutter....some people simply don't have the genetics/skill to do consistent huge weight cuts...While other fighters can cut huge amounts of weight all the time, with not much problems.Isn't that why all fighters cut? Khabib barely makes the limit and won't move up.
However Khabib is not bigger than the typical elite LW....they all cut around the same weight, Khabib doesn't stand out.