Keep in mind that if you buy a Switch console, your Joycon batteries die, and you want to play on the TV...well, you can't, because you can only charge the Joycons using the console, unless you buy the charging Joycon Grip for an additional $30. What's the difference between them? One has a charging port. Pretty ridiculous and obvious that Nintendo is trying to nickel and dime consumers. Am I going to buy a Switch on day one? Of course. Am I going to be happy about it? Yes. Am I going to be pissed when the batteries die and I have to play using the tablet, and then its battery dies and I'm just screwed? Definitely.
There is no "more powerful dev unit" - Breath of the Wild doesn't get a 3 fps boost on a console that's 2-3x as powerful as the Wii U. It's kind of hard to draw a comparison in terms of power between the Wii U and the Switch, but 2-3x is too high - RAM aside, it's more like 1.5x. The GPU is definitely more powerful, so higher resolutions aren't incredibly difficult, but the CPU isn't that far off. Double the RAM is nice - that doesn't necessarily let you do more complex things though, just more things at once - or bigger things. But it's nowhere near the level of Xbone of PS4, even though it can definitely output 4K video, but won't.