What about if simply remove "Active Topics" from the front page and make it visible from the Category down?

Instead have statistics about size of activities on a sub-forum?

And also have a link to the "more" search page in "Active Topics" for those who want to only reply.

Another ides is not remove "active topics" and to have a different rank system for active topics:
for example: sorted by count of posts and reads in topic in last 24h?