Notice how the outlines of the circle/number are red here? It would be nice to be able to achieve this effect in osu!
You would have a hitcircleaccent.png, or something along those lines, and also for numbers, and its colour would be multiplied by a new secondary hitcircle colour for the current object.
I could see the reason why we don't already have this having to do with it eating up more polygons, but I know you can figure out a way around.
Inb4 osu is not Ouendan: This is a skinning feature which skinners could find uses for beyond authenticity. It would be nice to have for its own sake.