Interesting idea I had the other day, what if there was some kind of mod or emitter that had a leaf graphic fall from a certain point, to give houses a genuine autumn look? I'm not sure if it's possible to make leaves fall the way they would in real life, but I'm thinking if it is possible, maybe have a selection of bricks that automatically start spawning leaves, so all you have to do is place one of these bricks over your build.
The leaves stay on the ground after falling, and you can use a new tool "rake" to move them around.
Just a thought, I have no idea if this is possible at all, but this is suggestions and requests so ya never know...