The idea of turn-by-turn strategy games is to allow the player plenty of time to sit down and think about micro-managing, tactical moves to make, etc...
However, turn-by-turn is lacking some kind of realism. You can't "intercept" ships when they come your direction. If I have a ship that can move 15 parsec, he can simply fly over an AI ship that is limited to 3 persec. While in a RTS game setting, the AI ship could try to intercept my vessel, forcing my own ship to take evasive manoeuvers in order to pass by without any violence.
A fleet well positionned could virtually blockade whole areas if they were set to "intercept" (as long as they can destroy their opponent). RTS, on the other side, would lack what we all love: FREAKING TIME TO THINK AND PLAN!
That is why I propose the "Partial Real Time" setting. The idea was implimented on a limited scale in the game Star Wars: Rebellion. The game was real-time, but there were different time frame. It was.. imperfect, because something bad would happen when you chosed "fast forward", and you would not have the time to correct it (when 2 months pass in 5 seconds...)
Now, what I would propose is "Partial Real Time". The whole game acts in term of "time unit" (= 1 months?), however, the time flows constantly. It really takes 1 full real-time day to spend 1 time unit in "real time". So, in "real time", there wouldn't be much happenning. Plenty of time to plan and act.
But, when you have issued all orders. When all ships know where to go or what to do, when all planets know what to build. When all scientist... you see the picture, right? You could press the button "to next event". So the game would automaticly jump forward in time to "when something happens".
Example of "something that happens":
- Planet finished building something
- Tech researched
- Ships arrived at destination
- Ships sees something on sensor that you triggered. (no point stopping the game for every freaking ally freighter).
- Ships has something unexpected
- 5 time unit passed without a thing (the number of "time unit" would be choosed by the player. Do you want to go forward small steps by small steps?)
(note, the last one is to allow the player to be able to keep an eye on the general situation. No way I want to jump 30 time unit in the future )
That way, we still would be able to micro-manage the entire empire, but include real-time strategies and fleet deployment.
(NOTE: We could even include communication delays for communications between governements, or between a ship and a governement?)