I've found that the shield wall works amazingly well, as it should vs massive blobs. I only put archers on loose, as they'll normally skirmish. I often take my cavalry on a flank and rear charge. Works well. The AI seems to respond well. After the initial clash that I tend to win, they will sometimes regroup and choose a different strategy, ie, circle on a hill for example...
What is key, is that it depends on their commander. If you take out their leaders, you'll face a mindless mob that is easy, but slow time to destroy, but if they have a decent commander, the AI does some interesting things.
I didn't know that the troops deployed in order that you have in your party screen. So thank you OP for that tip!
If would be cool if you could order Cav to attack Archers or something, but I wouldn't want a pause button. It would ruin the immersion for me, and make it too easy.
That said, a fast forward button, or skip end of battle when it is clear you've won and are just mopping up would be great.
Armour seems to work well for me.