Another Potential Solution to Consider:
An idea that has been thrown around the community, originally suggested by Brandis in an older forum post, would be to Limit the distance the player captain unit can separate from his/her respective Ai units. A reasonable distance would be about 10 paces/steps or less so as to ensure that a player captain unit has to stay with his/her troops and couldn't run off on their own to engage in the exploitation of enemy Ai units with the above mentioned strategy as they would also have to risk losing their Ai units in the attempt as well rather than just a single unit, which would discourage players from using these "cheesey" strategies in favor of more organized and command based gameplay.