• we need the track course as a spline (probably possible)
• we need all geometry in standard 3D formats - don't know whether TM editor has export to something else than their own format
• because of the gameplay concept we need collision borders for the track - don't know whether something like this is possible in TM editor
generally there are two parts in creating a track:
•*creating the track itself: this is already very very easy in something like Cinema4D/Blender/etc. basically you just need to track the spline points around. so not much is gained by a track editor
• creating the decoration geometry to make the track look cool. this is hard and track editors solve this problem by allowing users to just place pre-fabricated objects. i don't think tracks made with pre-fabricated objects look all that cool though.
i'd be happy to see either import options or additions to the built-in 3D editor made to facilitate easier track building but once i get some time to work on CB itself i will probably work instead on the #1 request with the game which is improved steering feel.