And that's even after leaving aside all the bugs.

The achievements are designed around making suboptimal/meme decks, and playing them in queue. So you have

• The players who put together a meme deck, get matched against ****-queue brawl players, and are unhappy.
  
• The players who just want to play a normal match, get matched up against a meme deck, and are unhappy.
• The players who didn't read the small print on the achievements and don't realize they don't meet the requiements, and are unhappy.
  
• The players who repeatedly play the Yargle Day event, only to find out afterwards they made no progress on the achievements, and are unhappy.
  

With all of this gated behind a time limit for maximum FOMO unhappiness.

An event like this should be self-contained, and not mix into the normal play/brawl queues.