These are untried, untested ideas, mostly"borrowed" from or "inspired" by various rules sets.
Possible turn sequence:
1. Roll for Action Points (AP)
2. Act (Fire, Move)
3. Conduct Hand to Hand Combat
Action Points: The active side rolls 2D6. The result is the number of AP that side has to work with. If the result is doubles also draw a random event (card, chart, or other mechanism). AP are spent to move or fire (or other possible actions). Hand to hand combat is separate and costs no AP. Disciplined troops, like British Colonial armies, can use up to 2 AP per unit. So a unit could move and fire, fire twice, move twice, and in any order, so they could fire and then move or move and then fire. Undisciplined troops, like natives, can only use 1 AP per unit. The player decides which units act when and how.
Each unit spends 1 AP to move or fire, where a unit is defined as 1 individual, 1 stand or group of figures or 1 stand and attached individuals, acting together, doing the same actions.
Some of my thinking behind this: It's simple, with 1 die roll per turn. It gives the player control over which units act if not all are able to. It gives disciplined troops an advantage over undisciplined ones, which, to my thinking, is important in Colonial games and some fantasy games. It gives me freedom and flexibility to add to it later without changing the basics. For example, I could add other types of actions such as demolition of a bridge, breaching a wall or barricade, and other engineer/sapper tasks. I could add some actions that take more than 1 AP to complete (in a single turn or over multiple turns). Or I could have modifiers to the die roll, for example, a very good commander might add 1 to the roll. I'm sure there are downsides to this idea as well. Of course, this is not a new or original idea either.