Also, keep in mind, with changes like these it is best to give it some time and get used to it, and then make a judgement. Work for it for a while. Then switch back to Rhino 8, then tell us what you think.
One of the other reasons for recoloring is also a functional one: since dark mode exists, we have had light and dark mode icons, because the dark outline didn’t work in light mode and vice versa.
These icons work better with both.
