Palisade walls should be a cheap, fast and common defense against the wild, at least in early game, or In frontier borders. But It's currently not useful. Horses can jump over it, it's gates consume steel, even making more sense the gate module of wooden gates be 2 doors, locked with and large board or log.
-Create a Primitive Gate Module, that consumes 15 boards and some nails, that is used only in wooden gate.
-Increase the size of the wall a little bit, just to horses couldn't jump over it, even with max speed.
-Reduce the wooden gate hp in 5% to balance for it not having a gate module.
With it actual cost, it's easier to rush masonry and construct stone walls(no, I'm not kidding).