This is a great idea so I would like to bullet a few features that would be important to at least myself.
Standard permission form including someone willing to step up and be our contact for the landowner/park service for that area.
A way to limit the number of geocaches within a particular park or development.
A way for the landowner to revoke or reinstate permission due to heavy traffic or impact damage to the area or wildlife.
Therefore needing the ability to display off limits areas to fellow geocache placers as well as areas that already have permissions and quotas.
This would be very useful for everyone, plus you could tie comments that the landowner would like everyone to know about a particular area when you seek a cache in that area (i.e. close all gates, pack-out all trash, don't pester the livestock, be alert for snakes, don't eat the purple mushrooms, etc.). This would be good information that is not always made available on the cache page or by the cache placer, and would truly be valuable to us geocachers.