2 Feature Requests
1) The ability to optionally define Source IP (or Range) for port forwarding
This would allow for better security when opening the port.
2)The ability in the Static IP, Addess Reservation page to type the IP you want assigned as opposed to having to accept the exising IP.
This would make it much easier to assign static IPs for certain things (for example all Desktops in the 192.168.0.20-30 range, Light switches in the 31-40 range etc.)
The second one is probably more difficut programmatically as it would need to check if the typed IP already existed, but most third party firmware allows it, so I'm sure it can be done.