Hey Joseph,
It looks like in this change you changed a lot of the giant natural=desert polygons around the Mojave to natural=sand. Can you say a little on why you think natural=sand is a good tag for these areas? I think that natural=desert certainly isn't well defined, but natural=sand doesn't seem like it's always right for these areas either to me. A lot of these "deserts" are covered in scrub or other plants. In fact, the Mojave Desert polygon you retagged overlaps with a tagged natural=scrub area: https://www.openstreetmap.org/way/934058828), but you can certainly see it if you zoom in to e.g. the Lanfair Valley (https://www.openstreetmap.org/way/165774302). I find that retagging these vast, often vegetated landscapes as sand weakens the tag meaning and obscures the actually sandy areas, like Kelso Dunes (https://www.openstreetmap.org/way/61011696). IMO, some of these might best be tagged as some kind of place=*, or maybe natural=valley.
Best,
Will