Allow for configuration of Access Denied and other Error message pages
The current SP error pages, both permissions-related and general error pages do not provide much detail as to why one might be looking at them. There is no way to use the "request access" feature on permission error pages without also giving OWNER access to people in the organization who should not have such power over a site.
My proposed solution would allow admins to add additional information to the error pages to allow for key contact information per site and site collection, actions the user who received the error could take which is more relevant to them and their organization, and effectively improve the overall experience.
Further, allowing for access requests to go to ANYONE and not just the owner group would be a nice improvement as well. I can allow permission management on a site while restricting other, Owner-based controls.