I'd prefer the right wheel instead of the left. The right wheel is fairly useless for me, it should be contextual... and this would be a perfect use-case.
I'm with you on the right wheel. However, I think people see the right wheel as a more "mission critical" control (when used with autopilot/FSD). Again, pretty trivial to make a left/right scroll wheel selection in a deeper menu. As you said, the hardware/functionality is all there, not really a big deal to write the code to patch it together.