What kind of ladders do you like? I can't believe people stopped using v8 brick ladders. They surprisingly work quite well. You have to look up, crouch and jump. It feels much more natural.
Player touch event ladders just get messy and you may end up hitting the ceiling or something. You can even abuse velocity ladders by choosing where you want to go in the air.
As for zone events you will either get stuck or unable to go down.