I think the problem lies with more than just a skin. The actual GUI is kind of ugly and I don't know if any skin can simply cover it up. I do remember Rufus or Luda (I forgot who) had a pretty decent nice theme though.
For now I would like to see the all blue theme from v4 (v5 used to have it but it doesn't work anymore) until the GUI can actually be fixed, but not as default. Just an option.
In the end none of your suggestions will fix the playerlist, just saying. It will help but it's still not the old default one.
