Really unlogical tech tree and AI

[Old Geezer]

Nobles don't dismount - ever - unless they're from the mountains and distrust horses like the Scots. (Actually we are too cheap to buy and feed them. We'd rather feed our peasants because we are so noble. It's hard enough just to find a staight stick over 10 feet long in the highland. That's why most of us left, twas to find sticks to whack the English with.)

[Rhyfelwyr]

From what I hear the English, at least just after the Norman Conquest, were pretty keen to dismount and formed a sort of shieldwall/phalanx with their lances.

At that point in time knights were not existent in Scotland. The dominant force were the Gaels who preferred to fight on foot or on little ponies, thier vassalls in the lowlands weren't even allowed to recruit their own troops. So there were no knights to dismount.