As per subject - it'd be nice to hide topics from the front page.
The use case is very simple - if I see a topic that I have no interest in, I'd rather for its spot to be taken by some other topic that currently sits "below the fold".
Hiding a topic should remove it from the front page only, but leave it visible on the group page. It would also probably make sense to mark the topic there in some way and have an "unhide" option there.
Alternatively, have a switch for the front page to toggle between "full view" and "view without hidden topics".