I completely agree with your statement about fish and plants. I have been moving things around for a year+ in my tank and it is obvious the fish love having a new scene as they explore unkown canyons and caves. About once a month something is changed, and no matter how small a change the fish really dig it!
+1 on the speckle paint on the underside of the bottom. You would like it, and the fish might too. I bet they miss turning the substrate. My son had goldfish for a time, and they always would pick gravel up and suck it then spit it out. It was fun to watch.