To start with your Kul’tiran: If they are primarily Kul’tiran, with all of their tongue in cheek fun but with a traveling Middle Eastern or North African aesthetic, I find little issue with it. If thats the established Wastewanderer lore, I don’t see much issue there either.
A people’s clothing is beyond just cultural, its practical. Clothing in the desert is not heavy, long, and loose because of some cultural signifier, but because it absorbs heat within the clothing but never transfers it to the skin, kinda a built in fan you could say as the thinkness retains the heat long enough to lose it, and the looseness offers airflow, not to mention avoiding things like sun burn/poisoning. So the aesthetic is primarily practical, but then made cultural in any variety of way either by the colors, styles, patterns, etc. If you’re wearing anything else on a hot, sunny, desert day you’re probably in for a bad time.
That said there are other ways to do desert clothing from the SW First Nations to those around the Taklamakan desert, or Western China. They chose to go with the North African, which is all good and well, though I feel as if the reasoning they went for it is less than great. I remember Uldum as just Indiana Jones. Indianan Jones of course based off of early archeological/anthropological runs to Egypt for the tombs which is just rife with racism. Though of course punch your local N@zi. Beyond all of that though which is out of our control, as long as you’re not going around as some orientalist stereotype, I think you’re fine.
To the Tauren: I’ve currently been maining a tauren and RPing one as well. Its near impossible to not fall into the trap, though I and my guild do what we can. We enjoy the tauren, we don’t particularly enjoy how badly they and First Nations are portrayed. The twist on the big angry dumb minotaur brute as largely peaceful, spiritual, and wise tauren is nice and very welcoming. The lumping it into the congealed First Nations stereotype and “Stoic Indian” not so much. There are a few ways we’ve tried to address it from being traditionally nomadic to quickly being sedentary. Don’t know what housing is just right yet, grand forges are new to us, what is farming, ect. Tauren come from a wide range of places in Kalimdor, we try to attribute certain regions with the First Nations there in the best ways we can. Those from Feralas have a more NW feel, whereas Barrens feel more Plains, Swamp of Sorrows Florida/SE, ect.
Highmountain was a mild redemption with different tribal traditions and cultures, more established buildings (though still not the plank houses you’d expect), and one’s geography did determine what they did (think of the Ironhorn tribe in the mountains). So we as players try to do a better job, but ultimately its on Blizzard to improve that image/representation.