I think "ground all sensors to the MS" and "don't assume factory wiring is good" are separate points.
If you're already buying all new sensors, or always intended to clean up/minimalize your harness, sure, run all new wiring. If you're keeping factory sensors and factory pigtails, I personally wouldn't assume factory wiring is shitty unless it's crumbling away in front of me, or something doesn't work right.
If you're already buying all new sensors, or always intended to clean up/minimalize your harness, sure, run all new wiring. If you're keeping factory sensors and factory pigtails, I personally wouldn't assume factory wiring is shitty unless it's crumbling away in front of me, or something doesn't work right.

