I would hypothesize that contact rate might have a few hidden flaws that might not always tell the correct story. On one hand, a pitcher with lots of strike outs and a low contact rate probably has some good stuff and the batter with lots of hits and high percentage can bat well. However, once you start to look for trends in the middle of the pack, on contact rate alone, things would break down. The secondary measure is definitely needed, but introduces another set or "error" in the data. I think you can spot some outliers, but not sure you could end up stack ranking based on any two sets of data with contact percentage being one of them. Contact below the ball often results in a foul ball whereas contact above the ball often results in a ground out. If you do proceed, the comment about using BABIP seems as good as a secondary measure as one might use.
I think it might be worthwhile to use the contact rate as a secondary measure when looking at a particular pitcher's effectiveness, or lack thereof, to see perhaps whether swing-and-miss is a part of the equation versus searching for "quality" in the general population.
If TrackMan would just become commercially available for under $500 than most of this discussion would go away and you could get almost infinite detail as to the outcome of each individual pitch and truly start tracking how balls are hit, including hard hit outs, to get a handle on how the batters and pitchers fare in mashing or preventing mashing.