Just witnessed some AI wisdom
I was warring with Tarth whom I'd previously made some custom units for. Deadly archers. The AI made use of these. In a recent tactical battle it had five of them, accompanied by a single spearman. Rather than advance the spears leaving the archers vulnerable, they were held back to defend. I slaughtered that army with my own range assaults, so I didn't get to see if the spears would advance to slow my assault if I'd have gotten in melee range. But just holding those spears back was evidence of this improved AI. It made me smile to see it.