This is just a thought..
Well basically i think you should add like a boss type missions with boss npcs that have abnormal hp etc. what most bosses have.
something like
a Gillian that has special traits the other of the same npc doesn't
same with shinigamis and vizards
lets say random npcs like shinigami or vizards go to hueco mundo and your alerted
and visa versa
(if your a hollow)
or Adjuchas and vasto lords that goto S.S.

Since your making it rp make npc espadas/Captains you must kill to gain there spots ^_~

This I like, it will receive great consideration.