Not all infinite scrolling is the same. These sound like generic criticisms of typical infinite scrolling implementations, not observations from the forum itself?
Discourse does infinite scrolling better than most things.It's not perfect, but it's a lot better than usual, and splitting threads into multiple pages wasn't perfect either as it often confused people. There are some quirks to get used to but I think it works well overall.
This is on the side and does exactly that (click to un-crop):
Or, if you're using a narrow screen/window, it turns into a progress bar at the bottom-right:
Shouldn't happen with Discourse, because it changes the URL as you scroll, to indicate which post you were looking at. If you go back or reload the page, you should still be looking at the same post. (You can turn this off in Discourse, but it'd be a bad idea.)
Bookmarks weren't imported, but you can go to the old forum and you can get the list, then re-bookmark them here.
If it's a huge list I can help by extracting it from the database if needed.
Yeah, keeping those working was important.
I'd love to have been able to only import "important threads that still have useful info and people are likely to link to or find" and lose the ~15 years of baggage and outdated information, but there's no way to know which threads those are.
A problem was just found (thanks to @enternal) with redirect URLs for threads that had quotes in the titles, which I'm going to fix today.
So there may still be some kinks. The automated import process went wrong in places. I've had to rebuild things like attachments, avatars and redirect URLs, while learning about 5 different programming languages and related frameworks to do it, and working on it non-stop for 2 weeks now. Still some stuff to iron out. But it's still better than the phpBB update process and the old web and database servers, which had become intolerable, so it's been worth it.