There are two reasons why we’re not getting content, aside from OW2. The first is that the development team values extensive testing. AndyB pretty much confirmed this a week ago in regards to why the experimental was so much faster:
I would say the bulk of the reason for their testing is to get rid of bugs, exploits, crashes, and so forth, but also because they overvalue their balance testing to a fault. I’m sorry Blizzard, but your internal testing team is not great at balancing. Their testing team is busy working on OW2.
This brings us to the second major reason, which is Blizzard’s hands-off balance approach. I think it’s terrible. It’s boring, doesn’t create a balanced game, and leaves heroes like Mercy to rot for years at a time. Blizzard has the ability to balance the game more frequently, they know the community wants them to balance the game more frequently. and has promised to balance the game more frequently, but is headstrong and refuses to do it anyways.
That’s why it takes years to do balance changes like giving Mercy +5 HPS, not because it’s difficult or hard to think about, but Blizzard would rather not.