I think this amount if fine. I dont think starting a new topic should be a "bonus" amount though. We dont want the forum flooded with threads about nothing.
I appreciate you thinking about this. We have thought of this, as DCD farming and spam are something that can become an issue, even in a community as wonderful as ours. We would hope that our users would not abuse the DCD system that is in place on our forums, however, if we find ourselves needing to move and merge too many topics for a specific user (or users), we are able to message them to request they stop. If a user chooses beyond that, then warnings are a possibility.
That being said, I expect with our forums being squeaky clean, there will be a lot of new topics cropping up. I certainly am not discouraging unique topics that encourage replies.
Wolfie