New forum software is a possibility we're looking into. PhpBB still is a major player and I understand that version 3 has many improvements over the older versions. If we are to choose a different one, I'd like it to at least have similar functionality and the option to transfer all current data.

Details like multiple themes have not been discussed yet. I personally want to aim for a reasonably quick implementation, where the focus is on creating better navigation and usability and not to spend a lot of time on a unique forum theme, like we have done in the past.