I haven’t fully read up on this thread, however I’ll provide feedback from our users.
All of our heavy forum users do not like this feature. The number one complaint is that there’s no way to easily get to a list of topics you’re subscribed to with updated replies without multiple clicks. According to them (this could be wrong, never used the feature), you used to be able to set default settings for these lists.
Secondly, the section at the bottom of topics has become unusable because it just shows you new posts at all times instead of posts with new replies. The previous setup used to allow users to catch up with topics they’ve been involved with by simply flowing through each topic. Now you’re forced to backtrack to the main page to view the next topic because the top 5 at the bottom always show new topics.