As I took over the maintenance of Tree Surgeon from Mike Roberts, there are millions (well dozens maybe) of ideas buzzing around in my head. We're tracking these ideas using the Issue Tracker on CodePlex. This will allow you to add new ideas as well as vote on existing ones. The strategy here (as is with all my CodePlex projects) is to have the team (which is building right now) focus the development on the most popular ones.
Please feel free to keep the discussions and ideas (via comments or work items) flowing as we evolve the Tree Surgeon tool to the next level.