I tried playing with it a bit. It is really hard to get used to the default theme creation tool by VLC. But I think given we can invest time and concentration and a lot of trial and error, it is possible to come up with a good theme. The best way to move forward is to start with a theme which is not very old. Currently, hands on with editing a theme which is made 2 years ago. Modified it and made it work with the latest VLC player version. I am happy about it 😉
You can get the VLC theme editor from here
Good luck sir. I am interested in the end result.