I am officially off the Cooper bandwagon. The replacement Hankook Dynapro ATM's in 275/70R17 E range were installed yesterday, no tire required more than 2oz of weight to balance, they are smooth and quiet as can be. (I had the ATm in 255/75 P-rated prior to all of this.)
Driving around on the Coopers the past several days, I also found the tread blocks very squirrelly, requiring constant steering correction; and they tended to follow road imperfections with gusto, requiring even more correction and producing unexpected vehicle movement. I tried psi at 32, 34, 36, 38 to see if there'd be any improvement, no luck.