I personally don't think a tank should have to be asthetically pleasing. I think it should look as much like a natural habitat as possible. Not every fish is happy in a pretty tank. Some fish like overgrown tanks. Some fish like tall tanks. Some fish like algae to cover every surface possible. I like to observe fish they way they would act if they were at home. That is art to me.
And that is art to me, too. Aesthetics does not mean pretty. It has to do with the perception of beauty and it sounds like you have a clear aesthetic in the appreciation of natural habitats.
I have been keeping fish for more than half my life. I started like everyone does, making mistakes and shoving plastic plants into epoxy gravel. The more I got into it the more I wanted to see how fish behave in nature. That's why I switched over to biotope tanks. I research a habitat as thoroughly as possible and make the tank look and act as much like that habitat as I can. But that's just me.
Ah, but it isn't! There is a whole community of biotope devotees! And you have just conveyed an aesthetic perspective for the consideration of everyone who reads your post.
Some people prefer abnormally manicured planted tanks, like the Dutch and Amano style aquariums that look so nice and perfect. However, I've never seen a fish in nature swimming around such a pretty landscape. I have seen quite a few fish gasping at the surface of one of those tanks to escape the wash of CO2 or cowering in the corner because there is way too much open water for them to feel safe.
While I enjoy Dutch and Amano style aquaria, my personal aesthetic includes humane treatment of fish and I am suspicious of CO2 myself.
My main point is that you can never have the definitive answer on anything in this hobby. Everyone has a different opinion on everything. Even well respected researchers like Walstad who write nothing but scientific facts have their critics. You can never tell anyone they're doing it "wrong." Even if they see and understand your point they won't change because they're doing it "wrong" for a reason. Criticizing a person for the way they keep their aquariums is about the same as telling them their religion is stupid. No matter your intentions, they will be offended.
I personally would criticize keeping fish in distressing conditions even if the fishkeeper had her or his reasons for it. That's because I have a value judgement for that. Other than that, if a person is doing something a certain way because it gives her or him desirable results then what is there to criticize? Sadly, we all seem to be a bit over sensitive and tend to perceive a few things as slights against our religions or fish tanks. Sometimes one can be read as presenting a statement as a definitive answer. I know any number of aquarists who were doing something one way, were informed of a better way, and who changed how they were doing it. I'll posit myself as a prime example. If risking offending somebody were always a roadblock to expression and the exchange of ideas we'd be in permanent gridlock but it pays to be conscientious not just carelessly offend people and certainly not to purposefully tick them off.
If we hold a thing in contempt before we learn something about it and evaluate it, we miss out on a potential opportunity for enrichment and growth.