No compute normals either? For 'regular' lateral displacements you need one at least, unless you work with redirects, vector displacements, or fake stones, which I do mostly too. It's a bit harder if you need to use a minimum slope for something like textures, but that too can be overcome by overlaying textures with maximum slope restraint.
And too many vector displacements also take up render time, so one compute normal or compute terrain and using lateral/normal displacement might yield the same speed. It's an interesting playfield anyway, trying to get maximum result with minimum nodes and speed.