Simple idea here. In terraria we only had wooden platforms made by the player. I think that they would work well in more shapes such as stone or branch and if they where spawned in the world. So like the branches on tress would be platforms, then you would find stone ones underground to help you traverse caverns.
I know, right? I felt a "lacking" in pass-through platform variety. Also, in the idea of it, one-way doors! I'm sure starbound has already made different platforms that you can pass through in the game.
I like the one way door idea more than the natural platforms. But those ones are also not bad, even dough I never felt like they where missing.
Great idea, especially with regards to trees. I've said in some other threads that I hope they include larger trees and more dense forests in the final game. I've always thought games like this would be awesome with huge trees to climb around on.