That would be great as I don't see a reason why AF's navigation feature should not work with other themes.
There is a precise technical reason: there's a difference in the way attract mode reacts when you change a display between displays that use the same layout file: using fe.set_display() function the romlist is loaded and the layout is reloaded, but when you use an hotkey or the displays menu only the romlist is loaded, and it's much faster because since the layout is the same, it doesn't reload.
Now Arcadeflow by default doesn't use the normal Displays Menu, so I wanted to use a trick to avoid layout reloading not only when going to next/prev, but also jumping to a selected display in _my_ menu: instead of using fe.set_display I trigger a number of next_display signals until the right display is reached. Of course if meanwhile there's a display that uses a different layout, everything stops because in that case the new layout is always reloaded.
I think that one of the strengths of AM is that we can mix whatever we want - it's super cool IMO to mix my great themes collection with arcadeflow and hyperspin (pcca) and I need to navigate between them of course. It's a legit prerequisite.
There will be an option to disable "fast display switching" altogether, although I'm also thinking of a way to use one or the other method depending whether there's a "non Arcadeflow" layout along the path
