Just doesn't feel right to not accelerate with the right trigger. And having rear view mapped to the left face button doesn't feel natural either.
#Needs option to customize controls
rotund crystal
clear mauve
You're right but just so you know there IS an option to change what button accelerates. At the main menu go to Extras > Options > Press R to go to Control Settings > Scroll down to Input Type and you can change the button there. And it should let you accelerate with both of the R buttons, not just one.
Also while you're there I recommend also setting Steering Sensitivity to 10 (option 2 rows below input type) and Set Race Camera to Dynamic (Press L from Control Settings and it should be the first option). Makes it feel like you're driving faster.