Hi Abe,
Disconnecting the brake switches will obviously disable the regenerative braking function, but it would also prevent the power cut off safety function from working if accidentally braking without releasing the throttle, and while stationary with brakes and throttle applied.
You should be able to either reduce or completely disable the Regenerative braking setting within the software using the USB programming lead to reduce the sudden jolts on the axle.
Even if regenerative braking is never used, the axle still needs to be secured properly to ensure it can't work loose with repeated quick bursts of the throttle.
I suggest you have a quick read of
this thread for information regarding securing the axle.
The thread diameter on the MP4 axle is 14mm, but the pitch of the thread will be either 1.5mm or 1.25mm, according the the axle fitted. Check out
this thread for more information.
Alan