I kind of think a 0-5 rating scale is sufficient, but what do I know.
And I'm sure there are more of you, than those of us that want half star increments. But there are quite a few that actually want and need it. Perhaps around 10-20% would be my guess.
The problem is not only applicable when rating your own music. What about all other services that uses half star increments or smaller. There's a lot of them. IMDB and Netflix comes to mind. Yea, I know that Netflix is no longer supported, and you have no ties to IMDB. But other services have, and we have the data. We have to do compromises to have the 5 star ratings give decent representation of the actual rating.
Without focus on integrating these services, I believe that MC will get a smaller and smaller user base. Local playback of media is going to be a smaller and smaller market. For me at least, that's another justification of looking into this now, rather than later.
I do not know what's up with the issue of list control. I don't know what it is, so I'll leave that to you
But I'm certain you could fix it quite fast if you wanted to.
The graphical representation however... Would that really be that troublesome? You could potentially fix two problems at once here. Why not create 2 graphical types of stars your self. One whole and one half. Add them as actual graphic files with MC, so they can be modded for those that choose so. We can give them the color we want, we can change to other stuff than stars as well. Beer glass icons would be my choice. It would be a pretty nice bonus to be able to control this your self imo. The standard characters are not really great for all of these operations anyway. A system like this could probably be used in other places as well? Such as watched/not watched icons. Labels for video resolution, audio channels and codecs used and so on.