Big battery +++++ (I needed a powerbank for trips before BV6000, now I know it will last 3+ days )
GPS+GLONASS +++ (Good sensor is a lifesaver)
Compass, Gyroscope + (Cheap sensors are bad and compass need calibration before use, better get standalone gadgets - last resort solution)
Quick charge, OTG, SOS, Interphone (Not really needed, but nice)

A. Big battery

B. Compass

C. Gyroscope

E. GPS+GLONASS

Big battery, but needs to be coupled with fast charge otherwise it takes 12 hours to charge.

If it's 'rugged' like the bv6000 then wireless charging would be a bonus, the covers are fiddly and will break soon.

Compass, gps and gyro? I'd view all three as standard on a smartphone these days. Especially a 'rugged' one. This is like asking if you should have WiFi and Bluetooth...

PTT, SOS? Nup. Never going to use them. Would rather have them programmable.

I agree. Wireless charging would be great because of the fiddly cover.

ABEF

and if possible a smaller size factor !!

MUST HAVE:
- Big Battery on a less cumbersome device
- GNSS + SBAS + GBAS/LAAS and FM-RDS receiver
- Good Camera
NICE TO HAVE:
- Usefull outdoor ensors (like compass, gyroscope, barometer, temp), but that function, that function in the right way.

for the flashlight button, i don't think it's so essential, since also with locked screen you can swipe down and turn on light.
for the fast charge, you can't charge the phone on a mountain or in a lake, so you don't really need it.....it would be useful if a solar panel would be implemented on the phone shield to let it recharge also outdoor