...and the most important thing: I don't see any indication of which edits were made after the last time I viewed the page. This is usually indicated by the text "updated since my last visit" between the edit summary and the undo/thank links of each revision.

We're going to add pagination to Flow board history within the next couple weeks, which will help the first problem that you reported. For the second part, we don't have that functionality yet, but we're talking about how to make that happen.