Wow, I wasn’t aware of this (although, now that I know, I’m not surprised).
Could you give some examples of the other hacks you noticed? Do you mean more customisation of the homepage, or was there even more? I’m curious as to what the other features were that Medium’s been slowly taking away.
Good points about the custom URL. I think URLs provide publications with a sense of identity on the web, so all three points serve to diminish it. One can’t really say “Here, look at my website” if it’s medium.com/something; the perception will be more like “Here, look at this publication that I have on Medium”. And people end up asking “What’s this Medium? How does it work?” rather than asking about your publication itself.
Of course, the same applies to Google and other search rankings, who will treat your publication as a sub-page of Medium rather than an entity in its own right.
Speaking of removing features, you probably noticed that several features have been removed for writers too: for example the ability to centre-align text or make the article title come as part of the feature-image.
I notice just now that you’ve created an independent Inside Blogging website in addition to the Medium publication (I think it’s hosted on WordPress?). How are you finding the traffic there, and are you able to move followers across or will you continue relying on cross-posting to retain Medium and non-Medium audiences?
Either way, I’m guessing it’s not as easy as if you’d had a custom domain name for Medium to start with.