With all these wonderfull modifications (http://www.twcenter.net/forums/showthread.php?t=464130) I decided to play a new 1813 campaign with Poland but now by roleplaying how would (was) a real Polish army organized.
I did some research (well, I just opened wikipedia) and found this:
"W armii Księstwa Warszawskiego w 1809 roku pułk piechoty dzielił się na trzy bataliony po 6 kompanii każdy. Posiadał ponadto artylerię pułkową w postaci 3 dział. Pułki jazdy natomiast złożone były z 4 szwadronów liczących po 2 kompanie. Pułk artylerii polowej liczył 12 kompanii po 6 dział oraz 1-2 granatniki. Pułki Księstwa Warszawskiego wzorowano na pułkach francuskich."
It basically says that an infantry regiment of Polish army consisted of 3 battalions of infantry and some artillery guns, horse regiment consisted of 4 squadrons and finally artillery regiment consisted of 12 companies with each of them having 6 cannons and 2 mortars.
I organized my whole army precisely in this fasion (more or less) and now I roleplay through my campaign by keeping all battalions of single regiment together, only rarely making exceptions (as they too happened in history).
I exchanged artillery batteries in some of the infantry regiments for grenadiers or light infantry battalions (finally grenadiers can be used as attachments to regular infantry regiments and not as whole units).
When a battalion is destroyed in battle and its standard is lost to the enemy the unit is forever disbanded and new battalion (with new name) takes its place in regiment.
Another time a single battalion or regiment (battalions act as parts of one regiment on battlefield too, not only on campaign map) distinguishes itself during a battle and in return is granted a special honour and gets a nickname - for instance when there is no higher ranking officer during a battle (no general) and the commanding unit shows great courage on battlefield, it will be called after its commanding officer (you can see his name after the battle).
Also, some units despite not being militia will act as purely defensive forces and be kept at one place all time. They get their special nicknames too, mostly after the region/city/town they defend.
What do you guys think? What else can be done to further enhance the experience and make the game a little bit harder without making arbitrary house rules?