Each feed gets 5 slots (or what ever number you set for the block) and each feed within the block is separated by the forum title. So in your case that's 50 post/discussions - that's a lot to browse! It is only a suggestion as a manual solution.
None of our courses here have that level of simultaneous activity across all the forums in a course. Instead the activity shifts from forum to forum as the courses progress. So I suggest tutors promote the personal email or RSS subscription options. Alternatively, they can highlight the most active forums with internal feeds and depend on the unread posts highlighting to guide students to check the forums.