Oh boy.
Hopefully blizzard actually does something about cheats in this game, but they've shown in past games they don't really care.
D3 is still filled with botters, hud programs and maphacks
WoW filled with botters, hacks that allow users to fly in pvp areas, and even allow dropping opponents (even in competitive and high level arena)
Hearthstone, somehow, filled with botters
SC2 and HOTS I'm not entirely sure as they're much smaller and harder to prove, but blizz definitely doesn't have a good track record.