If you think the visuals are the most complex bit of the player, you're way off; the player complexity is huge to make it "just work" seamlessly and intelligently. WMA has been in the player since 2000 (it was in the Rio Receiver, which builds from the same tree) but legalities needed sorting out before we could release it.
However, you could do a quick job and have something which appeared superficially to be much the same, but the last 20% to match the current player would take you several times as long as the first phase - there's a lot of hidden complexity in there behind what appear to be "trivial" features.
When we say there are many man-years of work in the player, we're talking man-years of work by people who are the best programmers I know, not by code-monkeys.
Hugo