Some of us want updated versions. Booting the vWii is annoying. You have to disconnect your Wii U drive, and plug in your vWii one. Then reverse that when done with the vWii. You have to actually get the vWIi booted. Mines complains about corrupted system files all the time, falsely, so getting it booted may take multiple tries. Then you have to deal with the weird cIOS that music games need. It could take a few tries, including hard pulling the power plug to reboot, to figure out which cIOS the game needs now. Who knows, you might even need to install a new cIOS. Then you have to deal with the controller. Take off the nunchuks, covers, maybe change the batteries, etc. Also, you've lost or broken the back cover of the guitar by now. By the time you get it working, half your beer is gone and you don't even feel like playing any more. You haven't played in a while, so you are rusty. You are already in a frustrated mood just getting the game going, and having to do warmup songs just frustrates you some more. You quite after a few songs and go play something else or just watch Netflix.
So yea, a new version that has a new controller with its own built in controller guts and a built-in battery, (hopefully), would be nice. You could get the digital version and not even have to change a disc, just boot right off the Wii U hard drive.