i would add my vote for a save feature, mainly for time issues, sometimes those missions take either a long time, or alot of tries....sometimes i play for awhile, and i have this theory in my head, ok ill play until something happens, then my base gets raided (new version), or i accidently hit the 12hr time boost, while my dropship is on the way.....opps cant save....i have to either play (really need sleep), or have to go from my last save which was 2 hrs ago.
if people dont want to save they dont have to, i know some people will use it to save\load, save\load, but that would be their problem.
implement this feature.