First of all sorry if this was already suggested but i think it would be cool if the AI bought the equipment based on the position/nation of the village/castle/town.
For instance: Bardaq castle is in Sarranid territory and there is more then enough sarranid gear of all kinds, maybe some realistic combinations like light/medium gear for village (cheaper one, since village is poor), light/medium/good for Castles and light/medium/good/best gear for Towns (they are the richest), for Nordic fiefs some nordic gear, for Vaegir fiefs rus equipment, for Rhodoks & Swadians knightly gear, for Khergits their own gear. Don't know if that's possible to add tho, but i think it would be an interesting addition. Maybe it would make AI's "choice" of equipment much easier and defender's looks more believable.
Ofc, some equipment is universal (like crossbows) and for balance sake it should be made available for all towns & castles but most of the body/head/foot/hand armor and weapons are diverse enough to assign them all over the place and make battlefields look different from each other, based on the region of the map but still make some sense (unlike some combinations we've seen around lately).
