I think the answer to this should be no. Imagine, if you will: your settlement has been stable for a long while. Thanks to your walls, the desert raiders are no longer a problem, and you can afford to equip your guards very well. You have, in past dealings, angered one of the factions, but you feel safe having built your settlement and/or battlements in a strategically sound region. As long as you have your walls, you should be safe.
One day, you notice some caravans are getting wiped out, each one progressively killed closer to your city. You realize an attack force is coming along, so you get your soldiers inside your city, get everyone inside and all that, and close the gates. There, you finally see it: a massive army just came by to try and wipe you out. But you are safe, knowing that they can't climb your walls and oh no, those men are carrying ladders with them! Is - is that a battering ram?!
You get your men to equip bows and arrows as fast as you can, hoping to shoot down the ladder bearers before they reach your walls. Sadly, it isn't enough: there's so many that any that are knocked out or killed will be replaced by another. They put the ladders on your walls and that chilling realization dawns on you: this entire army will be in your city, slowly but surely. Your only hope is that you can fight them off one by one, unable to handle more than one man at a time... and that's when the battering ram is at your gates. Hope you have an emergency escape plan!
If you want, you can imagine this scenario in reverse: YOU are the attacker getting back at a faction that's screwed you over and over again, and no amount of walls will stop you from entering that city. Come hell or high water, you are going to take this city as your own, wipe out all resistance, and use it as a staging point for further attacks until your enemy weeps for mercy!
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Regardless, I think the idea of having siege equipment would be a great idea to make a dent on larger cities. Even expanding on that, siege equipment should be available based on the complexity of the design: desert raiders could easily scrap together some wood to build a ladder for getting over some walls and raiding a small, walled-off village - or an organized raid on a larger city - while battering rams and maybe even siege towers can be afforded only by the most wealthy and powerful factions in Kenshi, taking days to build them and even longer to transport them (unless you build it at, say, a siege campsite: http://www.lofigames.com/phpBB3/viewtop ... 80&p=14863). If you want to go even further than that, then you could build the most lethal siege equipment possible in this setting: the catapult, or maybe even the cannon with enough research.
There should also be some kind of system to determine when you have begun and ended a siege, and who came out as the victor. The latter would be a little obvious, of course, but a little prompt telling you that there's a siege going on would be really appreciated if, say, you're focusing on another group doing something else in a farther part of the region. Also letting you know when it ended and who won, who lost and how many died per side would be just as great.
And if the besiegers decide to abandon their equipment to retreat, you could be nice and return their equipment to them... when you go and besiege their cities! Mwahahahaha!!
So, that's my thoughts so far. Thoughts?
