It's not as bad as you think. Without changing levels, they could have required a lvl 9 airfield for stealth surveillance drone, lvl 8 barracks for SEAL, and higher advanced buildings. I think they were reasonably nice. Your advice about pre-checking the missions ahead is excellent. For those that don't know, the mission spreadsheet is here:
https://docs.google.com/spreadsheet/...der=true&gid=1