Everyone can enjoy aesthetics, no matter what the score, so yes, they are important in my eyes.
As to who the greatest artists are, I would add Thomas (or really, Billy Bell for the bunkering he did) and MacKenzie to the top of any list. Strantz would be in there, for sure, but your minimalist-centric list seems kind of counterintuitive to me. Minmalists can shine on spectacular sites, but may not fare as well visually on other ones, unless they abandon their philosophies. Granted, many mentioned on that list have a nice bunker style and a tendency to random bunkers, both of which can be very aesthetic. And bunkers are usually a key to the aesthetics we seem to like.
I note Tyler has added Fazio to the list. His bunker style varies quite a bit with each associate, with some tending to plain jane (under designed and scaled to my eye) and others to the intricate gingerbread style, which is sometimes too much (although I don't mind it, some do) Overall, I think his pleasant effect comes more from his grading fairways into gentle valleys we seek in routing and from a large landscaping budget as much as bunkers.
For that matter, Doak's bunkers often seem about 5% exagerated in scale (lobes go just a bit too high in relation to the noses, for example) for my tastes, and Rees' work at Bethpage is similar that way. On the opposite end of the spectrum for Rees, I think you could boil down the millions of words of critisisms of his bunkers on golfclubatlas.com to being a bit too simple in shape for their size.
I am not criticizing anyone. I am merely pointing out that I give the idea of aesthetics quite a bit of thought. And its amazing how often (and I bet other gca's do this, too) we spend time pacing off bunkers to see what kind of proportions make a bunker look good to our eye. Designers in other fields have studied all the ideas of rythm, balance, etc. that most people will find visually pleasing. At some point, for all the artistry, there seems to be a little bit of math and science involved in creating it, rather than intuitive feel......