I used the Sunshine game streaming software and the WiiU homebrew port of Moonlight to get game streaming working on a WiiU gamepad. It's sort of like a bootleg Steam Deck, and it works surprisingly well, but it mostly just made me want a Steam Deck.
I agree. I think the problem with it is that it was just too complicated. With most Nintendo system what you see is what you get - with the Wii, those people having a good time swinging around their little Toblerones really are playing a game; the Switch really is a home console grade portable handheld thing; the WiiU manages to look like both those things without being either.