It's not the naturalness about it that I question. I question what it has to do with evolution. So man conducts breeding experiments and practices artificial selection to produce plants and animals with specific traits. That's selection, but it's not evolution. That's simply selecting the already existing gene pool to heighten certain traits. And man was doing this thousands of years before evolutionary theory was dreamed up.
Evolutionary theory didn't have squat to do with it.
See how easy it is? Even early agriculturalists, and even hunter-gatherers could do it.
And how did they learn this?
By observing nature. Just as, many years later, Darwin did. But he figured out the details and wrote it down.
But you say, "That's selection, but it's not evolution." When you select for certain traits (or nature selects for certain traits), other traits are less common. These small changes add up over time.
Fast forward a hundred thousand years and we'll see what we have. That's tough to do. Fortunately, with evolutionary theory, we can look backwards a hundred thousand years, or a million years, and see what we have.
Evolution is often slow, but paleontology and genetics provide a good look at the past and can see the changes that occurred. And, what to you know, these two different approaches support each other.
You say, "Evolutionary theory didn't have squat to do with it."
Sure, evolutionary theory didn't have anything to do with the changes in the past, as Darwin proposed his theory in 1859. But his theory (as modified and improved for 150 years) accounts for those changes and explains those changes.
Early folks through observation came up with a lot of the details, but it took the genius of Darwin to bring it all together and write it all down. And what he wrote down is the beginning of evolutionary theory--and it has everything to do with it!
You asked about macroevolution and I gave you a dozen or more examples in which chromosome duplications have produced macro changes.
Selective breeding takes advantage of mutations as well as alleles already existing in the gene pool. There is no physical or biological difference between natural and artificial selection.
Evolution is a change in the frequency of alleles due to differential reproductive success. It matters not whether the success is determined with or without human intervention.
Evolution includes changes due to mutations, and polyploidy is a mutation.
You asked for examples where evolution has produced something useful, and I pointed out that most of what we eat -- all of our domesticated plants and animals are the result of applied evolution.