I think many don't want to outright admit it but all recomendations I have seen call for a very large roof overhang to protect the plaster from weather. I have been brainstorming off and on for alternatives to plaster on
straw bale. my favorite idea in it infancy is to tile with rock/brick or actual tile, the same way you would tile a wall in a bathroom. even creating a gently slope downward on the exterior to reduce the pressure on whatever adhesive is used. I think it could result in a beautiful house.