I happened to be browsing /MoviePublishingHistory at the time of the switchover (after not visiting the site for months).
I clicked on one of the publication links, then pressed the back button, and suddenly everything was gone. It used to list all publications, including all obsoleted publications, in a single HTML document. Now it shows less than two months of only non-obsoleted publications. There is no apparent way to show more.
The page is still accessible from /Movies by clicking "List of movies, together with their predecessors" in the "Lists" tab, but it doesn't actually contain all movies, or any predecessors at all.
Is it supposed to be infinite scroll, and the scrolling is malfunctioning for some reason? I do have JavaScript enabled. I hope it isn't infinite scroll, because a nice thing about the old page was that everything was just there. You could press Ctrl+F and type some text and it would find it anywhere on the page. If you were browsing in another tab, and the browser discarded the rendered page and had to reload it when you switched back to the tab, it would scroll to the same position on the page. None of that happens with infinite scroll. (XKCD #1309)
Another thing I noticed is the hierarchy of obsoleted publications is no longer shown on publication pages. You used to be able to see it at a glance. Now you have to click a link, and wait for another page to load, and you have to do this for every single publication.