This is the first time I hear about Secular Web, but comparison to a discussion forum is pretty apt. Medium was, indeed, a crossover of forum and blog.

As for sinister intentions vs incompetence and over-engineering, I would say that it was all of the above – shoddy new programmers (IIRC Williams ditched almost the whole team around the time when paywall was introduced) combined with intent to curb influence of publications (many big, and I do mean really big and famous, publications left after monetization was introduced because their reach plummeted overnight), slow chipping away of search (e.g. there was an archive of everything written on Medium searchable by tags and publishing date) in favor of in house Medium curation to shoehorn readers toward specific kind of writing (though this veeery slightly improved during the last year or so), and complete redesign of reply system resulted in the buggy mess Medium is today. Well, you could say that the only sinister intention was that Medium was forced (by investors?) to generate revenue.

“Have you written an article on your experience of the old and new Mediums?”

No. Times and again, there were many (and more influential) people who voiced said problems better than I could ever do to no avail. So I didn't bother. I left some comments here and there directly for Medium folks, but they don't seem to listen. Hence I give up on that, too. Medium is what it is today, I've learned to live with it.