The Tc2M AI is good, however the battle is challenging when the player is just doubled by the AI armies in number of units.
Many times in TC2M the Oobs are done to have a bigger force against a weaker one.
Anyway i can say that game has a real good AI.
Concerning HWLG the AI is really well for the Corps level; Corps react to near threat, advance or retreat regarding the enemy in front and player moves; however the Grand Tactial AI needs some tuning in changing plans during battle and in exploiting player mistakes.
That said i am happy with AI in Hwlg.
For NTW i can't say, however i saw in total wars forum that many users complaint that General unit always makes suicides advances, cavalry just charges at the beginning of the battle... it seems more a medieval AI with Napoleonic figurines.