For 2.8, all the Blender icons were replaced with monochromatic ones. This is a very popular trend and a lot of programs are replacing their icons in this way, so it's obviously fine for most people, and I realize this is probably a niche accessibility need I have.
But, to use the new icons, I find I have to check each one every time to find the one I want. Instant recognition is no longer possible. For me, this extra cognitive load makes it difficult to use Blender for more than a few minutes at a time.
Blender is a fantastic product and one of the best examples of what open-source can be, but I for one will be appreciating it from afar, and remaining on 2.7 until there is a way to get more usable icons.