While I understand from a technological perspective why it isn't possible, I imagine the less tech-savy general public is not going to like it. The idea of still being able to play a game while someone else in the house is using Netflix is part of the appeal. I know Nintendo meant that the TV can still be used for non-Wii U things but I think one would regard using the Wii U to do something unrelated to games as essentially the same thing as using the TV to watch a DVD or watch TV. They whole selling point is to free the TV up and non-techy people will think that means ANYTHING. There will be more than guy who gets **** from his wife because they both assumed she could use the Wii U for Netflix while he was gaming.
Netflix is popular enough that in some households the "free the TV up" feature is going to be a questionable value because the reason to free the TV up is so that someone can use Netflix. I can't think of anyway Nintendo could have handled this but I don't think it will go over well.
This actually is why I'm not so interested in Nintendo systems having widespread appeal. I'm not married but I really just want a wife who will tolerate gaming. I don't necessarily want one that I have to compete with for videogame console time. Throw in non-gaming functions and suddenly "your" videogame system is hijacked by others and not to play videogames with. It would be like if my guitar also somehow was an oven and I would have to time guitar playing around dinner preperation. Lame. I can deal with relegating a videogame system to the TV in the basement but to be prohibited from playing games because someone else is using it for Netflix? That sucks! Why would I want that? "Fighting for the TV" is like a 1950's problem and now we have "fight for the videogame system" as a way to combat that? Yeah, that makes lots of sense. By including non-gaming functions, Nintendo is effectively undoing the usefulness of the "free the TV" feature. It has no value if the family is fighting for the Wii U.