i don't get this problem to the extent some of you guys seem to. My first 2 rows along my walls shoot straight at enemies as long as they're a sufficit distance away from the wall. However when my archers/ crossbowmen are shoot towards the inside of the walls, it does seem to be rather hinkey.

this needs a bit of work, but i don't think its quite as bad as you're making it out to be. though i suppose it might be something a bit more specific pertaining to the particular units and/or settlement type you're using.

something i'd like to see implemented would be round bastion type towers near the gates that would allow for good firing angles right against the walls. Also it'd be cool if your units threw rocks and boiling oil / molten lead on enemies at the base of the walls.

mottes would be nice too, as walls seam fairly useless once artillery gets brought into the mix.