The AI is so indescribably bad that it completely fucking fails as anything approaching strategy, either in the battles or on the campaign, and any single player "high level" play boils down to blatant AI abuse rather than anything tactical
Diplomacy system that might as well not even be there
Comically badly balanced unit buffs, god-tier army leaders, and magic, to where the actual army barely matters
Every campaign is just end-turn autoresolve spam by turn ~45 and the devs still find ways to make new campaigns that are even easier, and more braindead

And despite all that the game is cool as fuck and I love all the different races