The key problem is that you’ve lost the trust of the authors you want to attract. It’s no longer a place I can post and know that my content will be cleanly accessible to readers. I now think you’ll pepper it with pop ups and account demands.
It went from being a minimalist and trusted place to post, to now a feeling of feeding my own content into someone else’s machine and losing control of it.
You mentioned paying attention to the sentiment and linked to the HN survey where people explained why they don't like Medium. The top comment was someone explaining this exact reason.
It's highly admirable that you are on here trying to listen, communicating issues transparently, and working to fix problems. But I think you need to listen even more deeply.
Unfortunately this will push you into the depths of the business model that you won't want to change, but is the fundamental reason for medium's eventual failure.
Right now is the moment to save it, as you read this note!