Reconcile reservations with group policies
Reservations and group policies interact in ways that aren't always intuitive. Messages like "there are 32 nodes of type xyz available, but you're allowed to use only 16" could be caused by reservations, group policies, or both. Being more transparent would be nice.
Also, sensible behaviour when somebody attempts to make a reservation exceeding a policy limit would be good. "Sensible" might include warnings to the user and/or admins when the reservation is requested, temporary permission to violate the type limit during the reservation, etc...
We talked about this stuff and filed it away under "yeah, but not yet".