First post ayy lmao
I'm assuming that in OP's books "SHIT AI and are unplayable" is better than "Retarded AI?" Because I've never played a strategy game with worse AI than Civ 5. Hell, Master of Magic had better AI than Civ 5.
Let's see, for the rest of it...
Honestly I don't think the AoW series has ever had a meaningful difference in AI. AoW 1, AoW SM, and AoW 3 AI are all at roughly the same level. I've seen lots of people argue that SM's AI is better than 3 or 1? But there hasn't been any proof so far, and as someone who's played the crap out of AoW 1, SM, and 3, I really can't say that there's much difference. All three games you can steamroll the AI pretty easily at the highest level, and the AI's never particularly smart, it just cheats outrageously. Actually, come to think of it, at least SM and 3 don't have the whole "randomly march armies for no reason" that 1 had, so there's been at least some improvement. But if 3 is worse than SM, the difference is miniscule.
Of the HOMM games, 2 probably had the best AI. I never played 6 but of 1-5, 4 probably had the worst. Surprised it's not on this list.
Anyway, probably the closest I've come to seeing a TBS game with decent AI is GalCiv 2. Which... yeah. Isn't saying much. That being said, I'm surprised it's gotten so many votes. I mean I know the AI isn't the second coming that everyone makes it out to be, but it's still significantly better than AoW or Eador or any of the HoMM games (and I prefer AoW, Eador, and HoMM to GalCiv 2).