This reminds me of something I always thought fpsc needed, and thats the ability to make large flat polys to stick masked background images on and place into the distance of scenes, example, you want a masked image of mountains to add into a scene, or a far away castle, or a crashed space ship in the distance, or a row of trees. rather than build them in 3d, you use a 2d image, placed on a flat plane, then you add them to scenes for distant objects, no one has ever thought of making this, it would make a great tool. Perhaps your tree tool can do this, I havent used it yet, if you can have just one plane and alter its scale, so its not just a square, then it would do the job.
Speaking of tools, the best one for segments would be if we could make segments by plotting points on a grid, then extrude it to make a segment and then attach textures to the faces of the extruded shape, then save as segments, I was doing this over 10 years back with the brush tool in UnrealED. Would make a good tool for FPSC.