I still miss the "thread" view from the old forum, where you could respond to a thread as a whole, or to a particular post within the thread. This enabled you to keep track of the discussions within the thread. I think the lack of such could be a factor in the decline of the heavy debating that used to happen on the old board.
I also find it odd that if you go to active topics, you're always taken to the newest first, but if you go to the topics you've posted on or started, you're taken to the oldest.