battle AI single file formation

see here: https://www.reddit.com/r/totalwar/comments/73dm21/is_there_a_way_to_stop_the_ai_from_blobbing_and/

I've noticed the AI tends to form infantry into vertical columns when you advance, and not fan out in a line. I know the AI isn't a human, so is there anything I can do on my end to trick it into having more wide engages?