Many of us are here to collect various corals and watch them grow, not create a piece of art. Our reefs are ever-changing shape, color and light, and (to me) that's what makes it enjoyable and exciting.
I feel the purpose of a planted tank is to make someone feel like they are looking through a tiny window into a miniature mountain valley or rainforest. It's not about growing and/or collecting all the different plants. It's about creating a relaxing piece of art. Of course it would not be hard to create a freshwater inspired reef scape using nothing but rock and GSP. But that's so boring.
Beyond artistic concepts such as composition, color, depth etc., it's difficult to compare reef to planted aquascapes when they differ so greatly. I agree, reef aquascapes usually aren't miniature replicas of rolling hill landscapes or fine art paintings. I don't see that changing anytime soon. To be honest, I think most of the reef hard scapes I've seen are seriously lacking. They lack natural shape and feel. They lack an understanding of the basics of composition, applying the rule of thirds, golden ratio, etc... But if they're happy with what they have created, nothing else matters.
Crashing waves and currents built the natural reefs, quite literally by throwing rock and coral around randomly. That's how I did it. Scattered a few round rocks. Yet... Everyday I look at my tank and get lost in it, I could spend hours observing, admiring and soaking in the beauty.