The current problem I see with having 'intelligent' combat is that it currently doesn't exist. As is, you gain the most benefit for striking first. Hense, even if the computer tries to position for first strike, you just move back further.
It wouldn't be fair to the player if your tatics are penalized with a 'stall' and stalling should be considered legal moves.
Rather, I believe the solution is in game balancing. First off, and this may or may not be true as I have not tinkered with them yet....but pikemen or halbrieders should have some major benefit to being part of your army. Just like some weapons get backswing or maul, reach weapons should have, or be given, an ability that makes the player WANT to include them to take the first hits from your opponent.
Maybe have a 'first strike' ability attached to both the pike and the halbread, but have the pikes give additional bonus against mounted units and halbreids give additional bonus against foot-units. This way, you can position some of your troops to take the first hit, but still gain first strike...and then have your other units to obtain the tatical edge in movement or strength.
Maybe this is too complex and there should only be one type of weapon with this bonus type...that's for the developers to decide. However.....there is also the 'lance' to consider...mounted with reach can go a long ways. (sorry....bad play on words).