The set bonuses nerfs were applied without an official hotfix, with players discovering that the set bonuses amounts were nerfed ingame. They were nerfed from 17 to 50 percent, with the Unholy set bonus hit the hardest since it was the best performing SoD set bonus.
Even though there was a lot of feedback on PTR, who shared that the convoluted system would create a lot of issues if applied onto the live servers, Blizzard didn’t seem to pay any attention to it. The system is RNG dependent, and a player might get unfortunate with his loot drops, leading to a DPS loss if another player manages to pick up a powerful Shard of Domination or a set bonus from multiple SoDs.
In their update, Blizzard said that they’re looking to make further adjustments in the coming days, but won’t reduce the power of the SoDs to ensure that the players who invested a lot of time in currency to acquire them don’t feel left behind.
This system is not the first one to go through such a phase, with Blizzard releasing various seasonal systems in past expansions to incentivize their players to play more if they want to keep up with their peers. After receiving a lot of feedback, the problem usually goes ignored until it is too big to, before nerfs are rolled back or hot fixes released for things that should have been changed in the first place.