Here is an idea I'm pondering. When troops are in cover and you click on them, you get a "retreat" option.
The troops will head back to the nearest cover. If the nearest cover is occupied, they will push out the occupying troops and take that cover. So, the troops who were pushed out will advance.
You can theoretically reorganise all your troops, with this system. If you have DACB And you want ABCD, you just do this:
D Retreat, Retreat, Retreat.
You will have ABCD.
The question is, will this extra control be bad for the game's design? Summoning troops in the right order is key to success. However, like summon new troops, this takes time to shuffle them and requires quick thought. I think something akin to this may add to the depth and skill of the game.