I don't see anything in the current rules to suggest that someone with a higher leadership skill will be able to have more NPCs or droids in their party.
Last I heard the leadership skill would not influence how many NPC's you could lead due to the complication that would add to faction logistics. I have also never heard anything about leadership providing skill bonuses to NPC's, ever.
It is quite possible that leadership will have little influence in future features as it is already heavily used by existing ones.
Of course nothing can be said with any real certainty at this point.