Hi!
I'm using for the first time the Theme Designer... Really much more easy than touch each file manually...!!
Anyway, I really like to see a change in the way the theme customization is achieved... I'm a Infragistics AppStylist user and I think that the way Infragistics allow you to manipulate themes is even easier than the current VWG way...
They show to you a "live" screen, with all the controls that you can customize so, when you change a property, it shows you mediately... (http://www.infragistics.com/dotnet/netadvantage/appstylist/winappstylist.aspx). Even you can use an existing theme as base for your own ...
Don't know if they patented it, but it can serve as an example to follow...
Just my 0,02...
Regards,
Daniel