First, thanks for all you're doing, _ck_, without guys like you BBpress would be dead long ago.
For me BBpress has one major advantage - tagging topics. I didnt find many (any, for real) forums with such ability right from the start, without any plugins. The only thing I miss is normal managing of those tags - renaming, splitting and merging... For now you have to manually open all topics under specific tags and retag them.
Is there in you plans writing a tags managing plugin? If it can be provided via plugin, of course?