I think they need to be careful it doesn't become defined by the smartphone compatibility. It needs a distinct identity. Otherwise people may just think 'well I have the best/most-popular stuff - e.g. Pokemon Go - on my phone already, so I guess I don't need that NX thing'
Compatibility or even just running their smartphone games makes sense, but I'm not sure they should really make much play of coat-tailing on the likes of Pokemon Go. It shouldn't be much more than icing in the marketing proposition.
I completely agree with this. The casuals will just play the mobile games on their existing smartphones. Why should they buy an additional handheld for that?
Nintendo has to wow people with everything beyond the mobile aspect since that should just be the icing on the cake, as you already mentioned.
If they focus too much on that aspect then more invested gamers could be further alienated by Nintendo's offering.
I'm really, really skeptical. They need to have something that knocks it out of the park for me to jump in. I haven't touched my New 3DS XL in ages and I've bought the Wii U just for Mario Maker, which I don't regret but at the same time I'm not exactly proud of my financial decision. Back then I didn't care about money. These days I'm saving every spare penny for a nice car so I'm less inclined to buy something that I might not be interested in a few weeks down the line.