Emulators like Dolphin (Gamecube/Wii) aren’t available as RetroArch cores. But they can be started from the command line. Retroarch could with a few small changes work as a frontend also for such emulators.
AFAICT only three things are needed:
1 support for special playlists that instead of cores includes a command with parameters to run. Something like this in the case of Dolphin
C:\content\dolphin\RMGP01.iso Super Mario Galaxy C:\dolphin\Dolphin.exe --exec Dolphin 00000001|crc
2 Support for boxart for such special playlists. That could follow the current boxart format. For example \boxart\Dolphin\Named_Snaps\Super Mario Galaxy.png Where “Dolphin” and “Super Mario Galaxy” match line 2 and 4 for the item in the special playlist above
When the user picks and runs a game from the special playlist RetroArch would start a command line command with parameters by combining line 3 and 1 C:\dolphin\Dolphin.exe --exec C:\content\dolphin\RMGP01.iso
3 A small script in autohotkey or some other language can easily provide a joystick button combo hotkey to close the Dolphin session and reload the RetroArch menu when the user wants to switch to another game or stop playing.
This could perhaps be added as an advanced, unsupported feature that advanced users activate in the cfg and then have to generate the playlists manually, once a playlist syntax has been established.
Wouldn’t this be a nice feature?
We wouldn’t with this have all the features that come with proper RetroArch cores (shaders, save states, …). But it would still be useful and people could use one and the same frontend for more emulated systems.