Quickly adjust the amount of spin you do while fully pressing the triggers. This is for the "Pressure" Rotation option, not sure how it will affect the other rotation settings.
1. Locate your Input.ini
2. Add these lines to the ini
3. Adjust as you see fit
The defaults are Sensitivity=1.000000, 0.95 is enough to switch a full trigger press from a flat land 360 to a 180, but experiment for yourself. If you go below 0.75 sensitivity, reverts will no longer work with the triggers. I'm using 0.96 currently.
4. Save and play
To remove those changes, just switch back the sensitivity to the default (=1.000000), delete the lines you added from the Input.ini, or delete the Input.ini altogether (the game will create a new empty one on the next load).
Example video using full trigger press with 0.950000 sensitivity.
There's an undesired side effect where powerslides aren't reliable with straight horizontal analog stick motions to the sides. You can get around this by doing slightly angled powerslides by pressing the left stick slightly up+left instead of straight left before pushing out the right stick / foot. Think 10 o'clock instead of 9 on a clock face. You can angle the right one down as well, and even slide it up to get horizontal. I didn't even know there was some analog control over the powerslides.