Yeah, the Switch seems more like a technological sidestep than an upgrade.
They didn't make a new console because they wanted to push forward. They made a new console because nobody realized the WiiU existed, and they had to abandon the sinking ship.
There are some differences, from what I heard, mostly in lighting effects and draw distance but other than that you are getting pretty much the same.
I think the switch os a technological upgrade but not all the way, as Nintendo never been into pushing to the limit. But the bump is good to get to a very nice portable / home console hybrid. This video cover the the first minutes of the game.