Obviously yes it quite possible to make threats and the like with human players, but when playing in skirmish, or with friends via LAN against/with AI, you don't really have much reason to maintain friendships with the AI late in the game as the only consequence to refusing a mission is losing some points from your relationship, with a actual consequence attached the missions become much more of a priority, but that doesn't mean eliminating the "give me crystal and I'll be your buddy" sort of quest, it just adds a bit of dimension to the opponent. Especially if happen to bluffing, then you (or the AI) could say "I'll nuke your capital if you don't give me 2000 credits, metal and crystal" then if they accept, you could simply invade them anyway and gain a little more benefit out of it. To work in such a mechanic into the interface would take 3 drop boxes and 6 or so options for each box, adding 216 possible missions. That would be some awesome Diplomacy.
