In order to use handheld ranged weapons, you need to be fairly close to the edge of the wall to fight attackers or you aren't able to get the right angle. This also applies in most cases to siege weapons if you are trying to stop rams, or if early enough players trying to kill the guards. This also puts you in range of players on the ground - which is fine. PVP combat should always allow you the means to fight back.

Getting pulled off the wall into AOE zones from meatbag catapults or groups of players looking for falling players doesn't give you many options. Even if you don't end up on the ground, you can find yourself in places that are difficult to escape from. One example is at keeps - if you are using oils on the inner front door attackers. There's a small ledge on the inside of the main hole that I've found myself dragged onto a couple of times. While trying to jump back over that, onto the roof proper, I've been either CC'd and shot multiple times or hit with DC again and landing on the ground in that area is not a recipe for survival.

I've also been dragged off an outside wall.

Just like, stand back a bit instead of at the very edge? If you stand at the very edge you're asking for trouble. If you need to stand there then block cast and you can't be chained.
Idk what it is with players asking the devs to dumb down the game instead of using the tools at their disposal to overcome a threat, it's supposed to be PvP, players using unconventional tactics to get one up on their opponents should be rewarded, not punished.