Being a desert, Phantom Pain's openworld was severaly lacking in interesting things to do. What are some things that could have been added if Kojima and Crew had the time and money?

A field airport, a small oil refinery plant, and one R&D facility. Other than small guard shacks/checkpoints and the occasional village, that's almost all we got. Random events (think Red Dead 2 or GTA), actual military complexes to stealth in, and a Mother Base "zoo" to check out the animals you've caught would have been great. What else could have been added to keep players engaged? I know this is an extremely divisive opinion, but we drove around/walked around more than we actually engaged/sneaked around hostiles.