I still use XMMS, which has a very similar UI. Because I love it. (I tried Audacious but it was slower and had unicode character problems, and similar problems with XMMS2)
I don't know about the entirety of Unicode characters, but I've been using Audacious since version ~3.1 in 2011 (now 3.4.3) and it's never had any problems displaying Japanese and Korean characters--if you're not using the Winamp 2 theme with bitmapped fonts.