I love the idea, it's completely sound.
Reading a few of the previous comments, I think a few people are just out of order.
E.g. the one that simply says "F u, this game 'sicks'".
Also, the one where they're pointing out the fact that the badges are worth 0 points. NG never used to have badges at all, and even now, it shouldn't be about the points, it should just be the fact that you have a badge showing an achievement.
I couldn't find any bugs at all, I played through it 3 times, each time with a different combination of units.
The only thing I can think of suggesting (and this is because I'm trying to find some way to criticise the game, no matter how meagre) is to make it a bit longer, for me it only lasted 2 seasons and one battle with the king.
I liked the idea of unique units popping up every so often as well.
I'd say you should definitely do a sequel, the way this story ends leaves it open for a fairly easy sequel.
Oh, and sorry for the essay...