At least for hardest, I could swear AI changes its pattern with every patch. I still play a lot of skirmishes, as I still feel like making too many mistakes on parts independent of the opponent (build orders, idling villagers, not training army,…).
I’m not sure it gets better, but there seems to be an ongoing development in this regard, which isn’t mentioned in patch notes, as far as I’m aware. Is anyone else feeling the same?