Pocus is showing again some already stated problems of AI strategic choices :
1/ Prefers lots of crappy light troops over less numerous strong ones - maybe it tries to optimize number of troops bought and/or maximal usage of each province resources individually
2/ And don't spare money to build castles - this in turn results in few resources, so more crap light troops..
I don't think any nation specific AI is required : all sensible players would favor Pythium legionaires, Abysian Hvy Inf or Ulm and Marignon Pikeneers over Barbs or Militia... the AI does the contrary