1) Is the door over the SD card and USB slots supposed to be removable (rather than just coming off easily when you dont want it to) ? So the camera can be connected to external power while mounted in its cage.

2) Dewarp is not maintained amongst the custom settings in 4K / 50P 5I see this is clearly documented elsewhere).

3) It appears that dewarp can't be set on the camera and has to be done via the app. Is this correct ?

4) It would be good to have a constant reminder on the screen as to whether dewarp and rocksteady are, in fact, on.
Rather than, apparently, having to connect to the Mimo app just to check, in the case of dewarp. Or swipe up and risk changing settings, in the case of rocksteady.

5) In the Mimo app I have to select the device, click "connect" and then, as a supplementary step, confirm that I want to "join" the camera (which I obviously do because I have just clicked "connect"). This with and iPhone 7+. Is this normal ? It takes too long.

6) It would be good to have the option of setting ISO values in 1/3 or 1/2 stop increments. Full stops are too big for fine-tuning exposure.

I, too, would like the screen to show RockSteady, etc.  As you mentioned, swiping the screen can lead to an inadvertent tap and change a setting.  

DJI; you should think about adding 'Go to Sleep' and 'Wake Up' to the Voice Commands list so the user doesn't have to tap anything to activate recording or shots.  More options for hands-free operation would be great .

When I have Rocksteady turned on, I have RS in my Live View display so I know it’s on. Although, I’m having issues right now because even though RS is on, my footage is not stabilized. Not sure why.