It's not the wanting of a new color palette...it is the scoffing at the current color palette as being third rate and only worthy of a student project comments. There's nothing wrong with primary colors and all games don't use the same shade. What this is is a purely aesthetic preference topic that is going to be vastly different person to person and so is best left to modding which is already available as Guppy stated. Calling the current scheme substandard and expecting the devs to overhaul it (when this one IS the overhaul of the original already) is the pretentious part.
The student project comment was out of place, but there's nothing pretentious about wanting a game you like have a professional-looking UI. Sure, it boils down to tastes, but if that was the general attitude of the gamedev world then there would be no UI/UX specialists nor sophisticated, slick UIs; there'd just be a basic, functional UI and an attitude of "you want better UI? Mod it!".
And after the UI, guess what else can be considered "purely aesthetic preference"? Textures! So then game developers could say, "It's in the eye of the beholder, so here are some low-res, programmer-art, *fully functional* textures, and if you want better ones, mod it!". And now you'll tell me that of course, graphics don't matter, it's all about the gameplay. But gameplay is influenced by graphics too, and a game's design encompasses both its gameplay and its looks. And we're all very happy about a17's new textures, the new looks of the incoming RWG, the new hi-res icons, etc. If 7 Days to Die had Minecraft's textures, it wouldn't be the same game it is now, even if you had the ability to mod better textures in.
I think a game is a whole and every part of it deserves some attention. There are great games with iconic UIs that would not be the same without their advanced design. There are games that are downright unplayable because of their UI (often not even because of functionality but because of its appearance).