Lessons from Civ4
Multiplayer 4X Games
Civ4 is the model for How To Do 4X TBS Correctly. MOO3's interface was just terrible all the way around, but the MP felt tacked and poorly thought out (and it was, when it actually worked).
Now, I'm not naive enough to believe that nobody else here (or the people at Stardock) haven't played Civ4, so what I hope is that they take those lessons to heart for an eventual multiplayer upgrade to the GalCiv series. I, personally, would LOVE the chance to crush a buddy in a nice MP game of GalCiv2.