Maybe, rather than playing the game on a global scale, we could do a "skirmish" in a particular area of interest for all or several of our players. Missions would include supporting/stopping a violent revolution in a country, investing/conquering a newly-discovered resource in an inhabited region, assisting/taking advantage over the aftermath of a natural disaster, etc. We don't have to be in an area for use of all our units, setting us up for using wise tactics as much as military force.
As moderator game master, you'd have to keep tabs on what we players gain in finances & equipment, control over all friendly, neutral, & hostile NPCs or unused playable countries (which I may have overstepped my boundaries in the story w/ Sparta & Libya), and control over any natural situation.
Maybe we should try again?