I really could care less. I'm a wii U owner but I don't feel "betrayed". They gave you some of the greatest games ever made this generation.
It's like, if I bought an ice cream right? And the specific ice cream flavor was only available at a local ice cream shop. And I had to drive 200 miles just to get some. It just so happens that only a few people bought that ice cream flavor.
Then one day, the local shop sees the potential with Spaghetti ice cream and wants to bring it to the masses right? But during the time of its exclusivity, I really enjoyed that spaghetti ice cream. Now, what sense would it make for me to get angry because if I'd known the ice cream would eventually branch out to different shops, I would have waited and not drove 200 miles just to try it. You already experienced the ice cream before everyone else right? So what's the problem?
What I'm getting at is, you've experienced a game that has been out for years. They're giving people choice of what to get, you don't have to get it if you've already played it. Nintendo's core teams are more than likely working on NX titles. But they have to make money somehow during the holidays, and what way is cheaper than re-releasing some of the generations' greatest titles on the cheap cheap, on a system with 5x the install base as Wii U. It's a license to print money at this point for Mario Maker on 3DS. Sure, no online uploads is silly, but it goes in line with 3DS's street pass feature. Should they have included uploads, and searches? Yes. But making and playing mario levels on the go is pretty solid.