The effort of the first thing is also wasted on anyone who already knows what it means.
Not necessarily. Having a more in-depth critique all-round can set a precedent towards future critique and help build confidence in other individual's ability to critique well as well. Using words that generalize things will just produce more of it, and eventually everyone is using quick methods to make a point that for most- may not understand or perhaps partially understand. It's like a form of leetspeak.
Think of why "Hue" exists in the first place. Imagine having to describe it every time. It's not just a change in color, because white to black has no change in hue. Nor does a change from blue to a lighter blue NECESSARILY mean one. Imagine having to explain Hue to someone every time you wanted to talk about it?
It should be explained more, why would you want to explain it less? The way you say that "nor does a change from blue to a lighter blue NECESSARILY mean one", implies that you have a bit confusion with hues. A dark blue versus a lighter blue is just a blue. What is changing is the brightness.
Yes the blue hue can change towards more cyan or purple, but these changes are like the changes from one grey to another grey. Light through a prism reveals specific hues that when diffused at a distance become blended and produce intermittent colors similar to greys when white and black are blended.
Everyone could learn more by studying the effects of light.
Every niche group has dozens of terms that make communicating about them easier. I don't care if "step reset", "ARS", and "DAS" don't mean anything to people that don't play Tetris. They're valid terms inside the community. If someone on a Tetris board asked for for critique on their playstyle and I used DAS in my critique, it would be just as valid as using Hue shifting on a pixel art critique.
I have never heard anyone use "greyshifting" before you, probably because it's easy enough to describe without a niche term. But if people started using it, I wouldn't be adverse to it.
Tetris is much less interpretive a medium than art. You have less control over what you can or can't do in tetris, and in those cases it makes more sense to be inventive for precise rules that people make up. Hue-shifting doesn't represent something that is made up, but it implies a type of look just by using it, and so those who could learn more without the term may be encouraged to follow it blindly.
I have never heard anyone use "greyshifting" before you, probably because it's easy enough to describe without a niche term. But if people started using it, I wouldn't be adverse to it.
Both terms are somewhat silly, but imo greyshifting is more so, because it basically is a stupid synonym for shading, whereas there is no good synonym that expresses what we mean with hueshifting.
Polychromatic fits..
polychromatic (comparative more polychromatic, superlative most polychromatic)
1. Showing a variety, or a change, of colours; having many colours; multicoloured.
2. (physics, of electromagnetic radiation) Composed of more than one wavelength.