My intention is to leave any development materials posted online available indefinitely, so both "old" mixes of Rival Theory will remain publicly available, although the video titles might change. I plan do do something similar with v0.3.2.1, the last build with the "beta art" still visible.
Also, technically I didn't get rid of all the tree billboards, just the ones you're able to walk near! Some of the 2D trees will still be visible in the backgrounds of 3D scenes, to save on polygons.