I guess you abit misunderstood this change. It means that current 4 pieces bonus will be given on 3 pieces, and current 3 pieces bonus will be given at 2 pieces along with already existing bonus. At this example:
It will be smth like^
40% str AND 20% phys resist.
3 dru skills AND 20% max life.
But for some balancing reasons i sould change this abit for, let's say, 2 pieces:
40% str and 20% max life
3 dru skills and 20% phys resist
Or maybe 2 pieces for dru skills and life and 3 pieces for DR and str, 'cause having awesome 20% DR and 40% str for just 2 ANY set pieces from here would be abit too much.
And there's some another nice examples (if stats won't change alot) like:
Getting nice proc, resist and even reanimate isn't bad (if second pointless claw here will be removed and some item won't be changed to assassin only)