I've been tinkering with siege rules for Conqueror: Fields of Victory on and off for years. I'm currently in an "on" cycle.
Though I'm not sure what will come of it, it's fun to do some recreational game design, especially when it involves cool figures and a neat custom-built castle.
One of the great obstacles is integrating siege warfare into a system designed for open-field combat. In the close confines of castle courtyards and along battlements, things like wheeling and formation changes just don't apply.
I also want to ensure that I'm using the right amount of detail. That was the hallmark of the original system and I want to retain that.
At this point, I'm looking only at the culminating assault (hence the name) rather than the strategies of a siege (undermining, blockade, etc.) so that the game moves quickly. I've been tinkering with a grid where each player picks an option and that sets up the type of battle, but it's getting somewhat complex.
In the mean time, the assault ladders are being placed and battle beckons.