Yes, I'm sorry but who actually needs them?
People who use emulators have their roms already classified in their HDD by system in different folders. This playlist system looks great for someone having a mix of roms for different systems in the same folder. But honestly who does that? And besides that why doesn't it pick all the roms inside the folder??? Who needs validation against a server (after 4 hours adding my snes roms, I found half of the roms where not listed and that all the roms inside 7zip folders where spread there making it really hard to navigate)
I know retroarch lets you navigate through your folders and then pick a rom (and it supports 7zip which is great for people having full romsets). But then you won't see any thumbnail at all. Not to mention it never remembers the path where you were making it really annoying to continue navigating
If it were me I wouldn't spend more time trying to fix a system that just doesn't work. I would focus on the file explorer. This is how the great GX emulators on the Wii worked and we were very happy about it
This of course is just my opinion, but I see people constantly complaining about all this (good luck making thumbnails being displayed, I almost cried the day I finally managed to do it) and I think it could be improved in lots of ways by just giving up the playlists idea