Hmm...! All very good points! I can definitely put all these to good use. Thanks for the input!

I also thought up another point that stumblers upon this thread might want to consider: It's possible that smaller walls (as in, walls used to defend a valley pass or the like) would be build in such a way as to maximize defensive capability. For example, one might curve or square off the wall so that enemies trying to get to the gate would be surrounded by archers and rock-droppers in so doing. This would likely be especially true in the case of castle and fortress walls, which are meant entirely for defense.