I think the Track Editor will be something closer to what V-Rally did about 10 years ago, you will probably pick a venue, closed circuit, city, rally etc.,
layout your track design & some other basic parameters, finish. The software will then fill in the blanks such as adding buildings & trees. I use Bobs Track Builder,
but it is only a vehicle to building a track, you need other software to create the objects, such as 3d Studio, Sketchup, 3DSimED, Photoshop to make it all possible & a lot of time.
What makes a track stand out are those objects such as Dunlop Bridge & other iconic things that have to be created.
PD will more likely go the route of Turn 10 with limiting the ability to import images into the game. But like I said earlier based on something like V-Rally,
it could create some interesting and unique tracks, but will have trouble replicating real world tracks because of the limited ability to create objects & import textures.
