Good points.

I already use FD to make peace, it ameliorates a little but the gap between military and diplomacy AI means you get the peace until the military AI moves something to break it again. Better than nothing, without FD you don't even get a ceasefire, just a lull while they build up for another attack. Sometimes I find saving, quitting and reloading (which resets the AI allegedly) after a ceasefire stops them immediately leaping into another war.

Funny thing is, I already use smaller armies (no more than 14 units, often against AI full stacks), which immediately puts me on the defensive since they outnumber me.

I usually station my cavalry in reserve behind the line, maybe I need to push them further out to the flanks to attrack the general? A cavalry duel is at least a little more thematic. Though I'm wary of that resulting in getting some spearmen charging across the battlefield to fight them.