Right now, in order to allow others to rezz on your land, you risk your existing buildings/textures. A "landlord" mode would be nice. Allow you to let others (read tenants) build/modify/place their own furniture etc, and possibly even texture specific planes of your objects, I.E floor, with out them modifying the ceiling below them.
Let Lock act like Lock, and Lock the object from editing/modifying except by owner, or other criteria Lock with Move/Position turned on item to be placed.
Let Ban and Access Lists work, let Buy Pass work.
just a couple of quickes off the top of my head.