all pvp modes combined dont even touch the quantity of individual players who do mid level keys. You could quadruple the pvp community and still not even come close. If people want to smurf and destroy the ladder then as far as blizz is concerned its a you problem. IF it requires gladiator level play to win a match at 1600 then thats what it takes to be 1600.
My point is that if you think blizzard will be doing anything to ever ensure ladder integrity they wont. It doesnt happen a lot but ive had the same player in some of my shuffles and BGB on from tich. Intentionally throws matches and brags about it… reported him a long time ago. Hes still playing. The ladder doesnt matter.