Normal and/or displacement maps should be plenty to fake the effect you want. The only time it will be noticeable is at the corners since they won’t jut out of the silhouette. The way they are currently built might cause you a lot of headaches in your workflow down the line. You can also look into parallax maps; there’ s a thread on this forum about them.
You can also procedurally tile (and even randomize with some clever working) materials (normals/displacements/parallax) like you said you can with your wall geometry.
Keep in mind there’s usually very good reasons things aren’t done a certain way.