I think I understand what @hellekin is describing.
Have all topics with unread messages (and new topics created since last visit) listed at the bottom, so one can swiftly go through all activity since last visit. And when one finishes browsing this activity via Suggested Topics, the listing looks like this:
Caught up and ready to view the latest as it rolls in.
This, I feel, is related to my own past requests regarding new/unread indicators.
@hellekin, when you scroll down and check out the suggested topics list, it should have all topics with “unread since last visit” messages within them, or new topics entirely.
In user prefs, I suggest selecting “since last visit” for when to consider topics new.
Also possibly relevant:
Jeff, you already know the score. 