I am one of those players that really liked to keep a high K/D ratio. Call me vain, perhaps, but I like it. The issue is that at the start of the game, we are given a bunch of units, many of which I do not want to invest in researching to upgrade. However, as long as they are alive, they are costing me in daily upkeep, which are resources I would like to put elsewhere. I could simply suicide them against an enemy to kill them off, but I would rather not, since that would totally wreck my K/D. The option I am looking for, then, is the ability to "retire" a unit, whereby the unit simply disappears. To prevent artificially high K/D's, you could disable this for units currently in combat.
Alternatively, if the designers want to get fancy, perhaps you place the unit on "reserve" status, a process that takes a couple of hours (like Embarking and Disembarking) and when finished, the unit becomes an immobilized militia unit of the same level as the original unit, and only has a militia upkeep cost. To take a unit off of "reserve" status would require a 12 hour mobilization period like for paratroopers, during which the unit still cannot move, and retains the defensive stats of a militia unit. This would allow players to reduce the cost from units that they do not want to keep, but be able to recall them in case they start getting their butts handed to them and need to call those forces up again for defense.
Alternatively, if the designers want to get fancy, perhaps you place the unit on "reserve" status, a process that takes a couple of hours (like Embarking and Disembarking) and when finished, the unit becomes an immobilized militia unit of the same level as the original unit, and only has a militia upkeep cost. To take a unit off of "reserve" status would require a 12 hour mobilization period like for paratroopers, during which the unit still cannot move, and retains the defensive stats of a militia unit. This would allow players to reduce the cost from units that they do not want to keep, but be able to recall them in case they start getting their butts handed to them and need to call those forces up again for defense.