Wouldn't mind having it hidden in my own library. Plenty of games I'd rather not know existed. (Not counting removing then from my library, I bought them, maybe someone will want to play them some day)
You can already hide them in your library, it's in the right click menu, you can find them by searching for the title, or just typing the first letter of any game title and scrolling all the way down and opening your whole hidden folder. I wish they'd add slightly more features to the library sorting though. Folders would be nice.