Heroes o Might & Magic III

Having gone to Heroes IV right when it arrived, I never realized that the AI in Heroes III is very competent.  Heroes IV basically had no AI that I could discern.  The missions were like ride down this coast killing wolves until you get off the island - no interaction with the enemy.  Heroes III just kicked my ass again because the enemy came from a direction I didn't expect.
What Heroes IV had going for it was that it was very pretty.  They brought back an AI in Heroes V but that is for another story.