[BigNoid]

When there's no fanart (or in a non-video library node) falling back to the parent menu background or a fallback_XXX.jpg file sounds perfect to me. Configurable from the menu would be better but I understand your goal is a lighter skin :-)

With regards to artist slideshow, if its working in Aeon Nox 4 for Gotham and not working in Aeon Nox 5 on the same box that kind of indicates a problem with the skin as that's the only thing that's changed.

With regards to artist slideshow/visualisation, since there is an option for visualisation in background that seems kind of inconsistent to me. If artist slideshow is allowed in fullscreen but only visualisation is allowed in fullscreen AND background that is confusing. It also seems pretty baffling to have them both playing at the same time but that's a matter of taste I guess.

As for comparisons between Nox 4 and Nox 5, they're inevitable and I don't think you are going to be able to escape them. To me, Nox 4 is a direct continuation of the old skin with some nice tweaks, whereas Nox 5 is pretty much a whole new skin. I'm loyal to Nox 4 but Nox 5 is more stylish and uses dramatically less GPU resources. I can handle losing some functionality by switching to Nox 5, but I don't want to lose too much or I might as well stick with Nox 4 seeing as my box can handle it.

For fallbacks and music viz it should now work as I intended with beta 2. That is, it should fallback to main menu item images or in case of DVD Cases to random fanart.
In music viz it now shows artist slideshow when fanart is selected and you have the artist slideshow addon installed. It wont fallback to anything, so you should set the fallback slideshow in the addon settings. If the artist slideshow is disabled it shows library fanart and fallsback to random music fanart.