When adjusting images in LR I believe we all suffer from some degree of "color bias" or just plain "eyeball" inaccuracy! LR's single (1) pixel eyedropper white balance sampling tool provides very little assistance with "automating" white balance adjustments, since even normal camera “noise” causes readings to fluctuate widely. X-Rite's ColorChecker Passport plug-in samples a large area of each color patch in LR, and then uses the "average" of these pixel readings to calculate the 24 color patch values. The area sampled for my 5D MKII 21 Mpixel ColorChecker Passport images are approximately 100 x 400, or 40,000 pixels. This is a totally "automated" process, only requiring human intervention to establish the correct overall white balance with the new ColorChecker Passport camera profile. Unfortunately, LR's "limited" eyedropper tool makes this simple part of the process extremely cumbersome, inaccurate, and "unautomated!"
It would certainly make sense (and be very simple) for Adobe to add the option of using a larger user selectable area of the image with the eyedropper tool that is then “averaged” to determine the white balance. Without question, this will provide much more accuracy for those of us who use calibrated color targets like the ColorChecker Passport or even a simple 18% gray card, then using the current one (1) pixel eyedropper tool.
There may be times when a "single pixel" sample is the best way to determine white balance, but please do not tell me that "noisy pixels" in a large pixel sample area will make the readings inaccurate. That is the whole purpose of using larger sample size – To make the calculations more accurate. I am an EE with 45 years of analog and digital design experience, and have substantial experience with much more complex systems than LR's white balance tools. And lest we forget, film photographers have been using 18% gray cards for over 50 years. The analog colorimeters used for establishing white balance had a much larger sample size than anything near one (1) pixel size, and the accuracy was superb! Using a 100% digital workflow we should be able to do much better! By adding an option to the white balance eyedropper tool to select an area of pixels that I user adjustable I believe Adobe can achieve this objective.