After going through countless posts on here it would seem that almost the whole community would like to have a skirmish mode for Stronghold 3 as would I. Firefly is saying because they never intended to make a skirmish mode and that the game wasn't meant to have one that they will not be implementing it in a patch. I am a modder and have decided that I would like to up my replay value of this game so I am currently working on a skirmish mode for the game. I am going to script several difficulties of AI, currently I plan on making 4 difficulties; Easy, Medium, Hard, and Insane. The AI will not just make random base patterns and useless units. I will implement a big list of set castle patterns for the AI to follow, within the castle walls the building placement will be more random to an extent. The AI will intelligently defend its bases according to the difficulty setting and will make well composed armies to attack the player.
Along with this I am currently working to mod the physics of castle walls. I am trying to get a more realistic feel out of catapult and trebuchet projectiles hitting the walls. It will also take more projectiles to take down a wall. I am also making it so that regular units are not able to attack the walls. To counter this I am adding the siege tower as a buildable unit and turning sappers into ladderman. I am doing this because I personally feel it will greatly improve castle siege and defend tactics. My final adjustment to units if I can make it work is to have archers shoot together in volleys.
It will take me a few months to make and fine tune this mod, mainly do to the fact that I am in college and have school to contend with. When I am done I will make the mod available free for download to anyone who wishes to play it. If the majority of the fanbase here votes for any extra feature on top of what I am currently working on I will see if it is feasible for me to do.