My suggestions:
1.) Have gimble on camera operate past 90 degrees, (Straight Down) That way track / fly can fly forward (obstacle avoidance) while tracking an object moving towards the P4: Perhaps +10 (forward to -110 (90 + 20 backwards) This is the exact range of motion currently available (+30 to 90). (Currently the P4 needs to "fly backwards to track an object approaching)
2.) Able to "snap in" different camera modules (camera with different lens), FLIR, etc.
3.) Add Panorama control to Smart Controls. (Both Video and Photo). Allow user input for rate turn (angular speed), clockwise & Counter-Clockwise rotation.)
4.) Allow C1, C2 buttons to control "dry contact" for add on devices, Eg C1 Can Control a parachute deploy during adverse operating conditions., Maybe C2 could control EMERGENCY Strobe Light, or deploy a smoke tracking device: Have connector with 4 pin header easily accessible to outside of unit.
5.) Broken Prop, Engine fail, or other catastrophic damage mode: . Have sensors determine broken prop and try to land with three props (It may not be pretty) but a softer landing is better than straight fall. (eg cut power on two props rotating in the same direction, and full power on counter rotating prop)
6.) Add flight routing software (DJI Ground Control) for P4. This is a must have for anyone using drones for aerial surveying. This can be either PC or Mobile app developed routes. Or allow 3rd Party to create map and then download so Mobile App can import and run the routes. (Currently cannot import 3rd party waypoints!)
7.) Add bluetooth for downloading of all data, flight telemetry, photos, videos, etc. (only from ground, not in flying mode). That way never need to plug in cables or remove flash card.
Lastly I am completely new to flying a drone, I have about 3 -4 hours total. I picked one a P4 and it has been quite easy to fly. I simply cannot get over how stable the unit is, especially in winds.. The pictures are pretty good, (but not as good as if taken with better camera, albiet much heavier lens, which would be much shorter flights). It is a very good trade off and I would highly recommend the P4 to anyone, considering a quad-copter in anywhere near this price point.
Rick