Awesome game!
In my first game, I thought the Danish 2+1 units are undefeatable, since they won the initial dispute on the small land bridge against an English 1+1(+1) unit stack. The English leader was gone and everything looked grim. The Danish moved forward relentlessly, killing two other units. Then in their hubris, 3 squares in front of Maldon, they attacked a lonesome English infantry unit, 3 to 1. But due to a lucky queen of spades, they actually defeated the Danish stack, including their leader. The rest of the Danish horde fled the battlefield.
I really like the randomness generator. Since we're using the cards also for movement, literally everything can be drawn during combats. You can't meaningfully predict it. Thematically, I liked that decision. (By the way, I played with a 32-card deck if that makes a difference)
I also liked the art. Especially the cover image and the counters are a work of art. The map could show a little more terrain, but it's definitely functional and works well.
Maybe room for improvement could be to somehow encourage the players to move forward with their whole line. In my games, I usually went only with the strongest units until they were dead. Except for catching Danish units in -1 terrain off guard with my cavalry, there wasn't too much manoeuvring happening. Maybe I'm missing tactical aspects, though.
The rules were well written and did not leave much room for interpretation. I also wondered about the stacked leader movement, but you already clarified this in another comment.
I really enjoyed playing. Thanks for the entry!
PS: If a stack with a leader attached loses a combat, the unit and the leader die, right?