Don't get me wrong, I love the work you're doing to AA and I completely understand that these are just tests but to consider terrain system as today's standard it should have:
- a rich editor with sculpting features (possibly with texture mask option) to carve, smooth and raise/bump terrain geometry
- modern overlay material system to mimic different kind of terrain
- vegetation system (grass, trees) possibly with paint system
I repeat, don't want that these seem critics. I saw interior levels design in Xonotic and I said "Wow, cool", then I saw exteriors maps with terrains and I said "Wow, that's the ugliest thing I've ever seen in my whole life (not game related necessary) !"

IMHO, for terrains, Quake based engine should stick to OBJs hulls models. I think it's possible to create more realistic results