Has the suicide bomber AI gotten fixed at some point? That more than anything else has led to the game remaining unplayed after the first campaign for me.

In a game where a single hit frequently means the loss of an hour of gameplay you shouldn't have enemies who will try to kill you even when they would clearly die from their actions.

At least one of the patches (I think it was version number 1.2) introduced some global changes to the AI but I can't guarantee that everything's to your liking now. But note that AI is configured individually per level and enemy behaviour may differ greatly between levels, particularly scenarios.