I think it'd be awesome and have some of the same captains and some new ones and have Ichigo as a BAMF that only shows himself when needed or possibly make him another captain; i havent decided. (Please give suggestions, im working on it now!)
I'm thinking it should be after Ichigo's time. Keep some captains, have some OCs be new captains and have players choose to be either a Soul Reaper or an arrancar/Vasto Lord.