This idea is indeed very good, because if the wall is very oblique, it will make it easier for the stone to roll down, and the slope should not be too large. It will certainly cause a lot of damage to the enemy, which will reduce the losses on our side.
But many people forget an important problem, that if the city wall is tilted, it is not only easy to collapse, but more importantly, the city wall must be built a little taller to be able to make it well, but it takes a lot of materials and manpower to make a city wall, and many times it is cutting corners, who really bothers to do this? Unless it was time for war, the defenders of the city would think of it.
Not all the walls are repaired like the Leaning Tower of Pisa, the more inclined the better, the repair of the wall is to repair the higher and bigger, and the wall must be strong.
There are two ways to repair the oblique point of the wall, one is inward, one is outward, if it is convenient for the enemy to attack like the inverted slope, the enemy can put the ladder on the slope, then the attack will be more solid, so that it can be easily attacked, which is completely impossible to carry out.
If it is outward, it is also not good, because if the enemy is hiding under the city wall, then this slope is equivalent to making a protective umbrella for the enemy, the stone is not good to get down the wall, the enemy as long as he attacks the city gate hard, it is very easy, this is not impossible, so from this point of view, this is not OK.
In ancient China, if you build a city wall, it is very self-careful, especially when you hit Zhu Yuanzhang, Zhu Yuanzhang wrote the name of the craftsman on each wall, who if you let this wall collapse, you have to kill this person or deal with it strictly, so you have improved the city wall project, the reason why you did this thing, is because he suffered a lot, so he has to rectify this aspect fiercely.