I read that with the P3's you can hold down both C buttons and rotate the exposure wheel to adjust the gimbal roll in order to correct an unlevel horizon.

Is there anyway we can get that functionality added to the Mavic?

i would also like this to be assignable to the wheel.

There are some other usefull custom function which are assignable to the wheel on the Inspire 1 which can be toggled by pressing the right wheel.

As the Right wheel on the Mavic controller does not have a button press, it would be good to be able to assign a toggle to the C buttons that allow the wheel to be used for adjusting the other core camera controls including ISO and white ballance..

Yes a quick adjustment for the gimbal roll would be very helpful

Just as Droney McDronef mentioned, the wheel on Mavic controllers does not have a button press.
I'll help to pass your advice to our related team.

The Mavic did have this feature at one point. However, it also changed your exposure at the same time that it changed the gimbal. So every time you adjusted your gimbal this way, it messed up your exposure. Instead of separating the two things, they removed the gimbal adjustment feature.

Maybe it's a hardware issue.