So friend, the Wii U retroarch is very good, I recommend itMost of the time ive seen people on wii u purposely go for using emulators in vwii rather than retro arch so thats where my assumption came from but I will be honest retroarch is still a great option for people who prefer wii u mode
The Wii emulators injected into the Wii are only worth the ones that aren't natively available on the Wii, like the N64 ones, but otherwise run through Retriarch, you'll see that it's much better
people who still play wii emulators on the wii u are in a hurry to the past of the console when it didn't have any emulators natively, nowadays it is no longer necessary to use many vwii emulators on the wii u