Anyway, my only issue with a skin is its hitsound and transparency for smooth play. Like, I get comfortable hitting those circles with a nc hitsound and get comfortable reading the map with transoarent sliders. Somethin like those.
I use skins that don't take to much focus like Luminous (v2) (link, https://osuskins.info/skin?s=2474). IT doesn't have any numbers in the circles and that does have pro's and con's. The pro's is as i said before it doesn't take much focus and that when ever you get a miss, 50, 100 or a 300 it isn't distracting and in your face but the con's are that I really like jump maps but sometimes I become confused with the order of the circles. If i would change the default skin I would make the colors less vivid and the miss's, 50's, 100's and 300's less distracting.
i play with two custom skins: one reddish-pink, and the other one is a kind of blue you'd see in a rafis skin. this is primarily to affect how i play, since red scientifically enhances focus and aggression, while blue suggests a more passive and calm sensation. the skins themselves are not by any means perfect, especially the standard mode, but it is fixable.