Just Play on VH/H and you will get good battles , the AI is and always will be retarded so not much helps in way of getting them to recruit armies properly. VH is the best you will get.
And i find the Standard EB formations to be the best , with most of the formation mods the ai just sits on a high hill and dosent move or makes a retarded 5 mile line and still dosent fight , more or less just makes for boring battles , but thats just what i think of them.