Question Terrain generation vertex spacing & affect on applied materials.

I've been working on a terrain generation system that has been producing roughly the sort of terrain I want, however it comes with the downside of large steps from one set of vertices (the base plane) to the top of the cliff. The algorithm works by displacing vertices from a plane, so I'm wondering: what's the best method of increasing the vertex count on the side walls of the terrain? Initially I investigated remeshing the entire thing however I am concerned about the performance of executing a remesh every time terrain is generated.

Would this lack of vertices affect the application of materials to the terrain? (I guess displacement maps will not work on the wall).

There are lots of vertices to spare on the plane, how could I include some of them in the wall? Thanks!