Well until Paradox provides you with your ideal game, you can try Space Empires IV, you can even play it for free on Gamersgate Void.
It is a bit dated but you can get a whole lot of mods including ones that update the graphics. My only issue is that to fill the screen I have to manually change Resolution to 1024x768.
Although there is even a mod that runs it in a window. They also made the modding very easy even for beginners, so if it is not what you are looking for perhaps you can mod it into the game you desire. For MP they have a system called simultaneous movement. Basically everyone puts in their moves for the turn and then they are resolved. IIRC Diplomacy has similar mechanics.
It is a bit dated but you can get a whole lot of mods including ones that update the graphics. My only issue is that to fill the screen I have to manually change Resolution to 1024x768.
Although there is even a mod that runs it in a window. They also made the modding very easy even for beginners, so if it is not what you are looking for perhaps you can mod it into the game you desire. For MP they have a system called simultaneous movement. Basically everyone puts in their moves for the turn and then they are resolved. IIRC Diplomacy has similar mechanics.