Very interesting question.
I'm not the one to properly answer this, given my ability level and the fact that I've only really played with cheap rock hard balls, but I'd guess that if more courses were designed and setup like #2 this year, Shinnecock last year, Oakmont every day, probably Merion everyday, too, you see more of a gravitation back to control versus distance.
It's not for nothing that I keep Pat Brockwell's incredibly insightful comment as my tagline! I actually believe it.