Turn based tactical battles that may please most or all.
I think a good tactical battle would involve turn based 3D environment like the map environment in GCII. Logistics would still be in play, so that would help keep the number of ship down that could be in a battle. And like logistics you could research systematization, it would work similar to logistics but work within battles. So if ten ships enter a battle and you researched "echelon systematization II" then you would have 3 ships out of ten that can move and fire per turn, which could give advantages and disadvantages. With research you could be limited to 1 or 6 ships moving per battle turn or what ever your research level is at. One turn could consist of attacker and defender adjusting shields to front, sides, rear or what have you (like Star Fleet I - The War Begins! (I think it was that version)) . Then targeting ships and/or its components, and which square to move to and fire. Then pressing the next battle turn button for the next battle turn.
To elaborate on this a little more...
I'll be using the same 3 out of ten ships per turn example scenario for attacker and defender, of course this would change depending on research.
On entering a 3D environment battle mode the attacker would go on the attack first (this means "could" get the first shot depending on experience, and defender can only respond to the 3 ships that are attacking) and may have an advantage as described later. Now these 3 ships could be moved selecting pre designed formations or user controlled, or both (which ever works better). In pre designed formations a variety of formations would be available to select from, default would be (that is if you did not select anything for formations and moves) AI would choose best formation and squares to move to. Then adjusting shields or leaving it to the AI to adjust. Then you could choose ships and/or components to attack and/or attempt boarding a ship (if boarding is in GCIII), default again would be AI would choose best ships and/or components to attack or board. So on default you could be hitting next battle turn button until battle is resolved without getting involved, and you could intervene at the beginning of any battle turn if you felt it necessary, of course all this can be bypassed as described later. After selecting all your options or just hitting the next battle turn button, up to 3 ships from attacker and defender ( that is if both attacker and defender have the "echelon systematization II" researched) would go into action.
Depending on defenders experience they may have a response delay, so if a defenders ship had a response delay of 2 because of experience, that ship would have to wait 2 movement point before it could fire any weapons. On the next battle turn those ships that moved would have an icon signifying they can't move this battle turn, and up to 3 more ships can move and/ or fire weapons on this turn, this would carry on like this until battle is resolved. There could also be an option on the battle screen to skip to end of battle which you would just watch the battle play out similar to the way GCII does it now. Of course there would be an option in the options menu to skip the battle screen mode altogether. So the battle could play out in a part RTS (meaning you cant intervene in RTS part of the turn) and TBS. In this way I think it could please all or most of the different tastes that are out there that people have. It would have RTS and TBS, you could just control formations (maybe even player pre designed formations) or micro manage weapon firing, you can get involved in some of, or all of, or none of the battle turns. If you had 5 ships per battle turn to move you could control 2 ships and let the AI control the rest. So you decide how involved you want to get