The only reason I buy a Nintendo console is because it has its awesome library of games. Now actually allow me to rephrase that. I only buy Nintendo home consoles because of its stable of games. Its handhelds usually get great support, and most of my favorite handheld (DS) games are from third party. On home consoles though, it's another story. Nowadays most third party games either play or look better on other consoles, or are just not even available on Nintendo consoles. I honestly think that at this point it is impossible to expect most major multi-platform games to come out on Wii U or any Nintendo console for that matter. You'll either have to have another console or game on steam (I recommend the latter) unless you absolutely have to have Halo or the next masterpiece of modern storytelling that is the Uncharted series.
That's what I buy Nintendo consoles for nowadays, so yeah. I do have a few third party games, but I generally buy cross-platform titles on my computer.
Same. It will end up with at least 15-20 great exclusives by the end of its life that will more than justify the purchase, anything beyond that is gravy.
I will always get at least one other console to satisfy my gaming needs, I cannot get that from just a Nintendo console. I will never not buy a console that plays Nintendo games, even if that's all there was, but I could never restrict myself to only playing games on that system.