The concept is fascinating, remarkable, and honestly extremely exciting.
My problem is that the execution will likely be disappointing. The only kind of "portable console to main console" connection I've ever even heard of was the PS3's ability to link up with PSPs and PS Vitas, but that was extremely dysfunctional and you couldn't even use it to play games. NOTHING like this has been done on this scale before, and honestly I don't think that the processing power could possibly be strong enough to run the console portion of the device on the handheld portion of the device without a serious drop in performance, especially at the ranges that they were claiming the system could operate at.
Additionally, I feel like the system will be... well, fragile isn't the word for it, but there's too much going on. Too many minute little details and parts, especially with the multiple click-together connections, that could easily break. There are just way too many accessories and I'm wondering what would happen if you lost one of those small side-controllers that go on the tablet-looking part, which if you used this in public like the advertisement suggests you could, is entirely plausible.
I'm also wondering how much of the console comes as standard and how much is sold separately. The commercial shows two controllers, one being a more traditional looking one and the other being the tablet with the mini-controllers. I'm sure the tablet comes in the box (if it doesn't, then there would be some serious problems) but what about that controller? What about additional mini-controllers for four player games, (since each individual mini-controller can separate from the tablet and act as its own controller)?
And that brings up the final concern - price. How much would getting the full kit-and-caboodle cost for this console? It's truly next-gen, and it has the potential to be ridiculously powerful. So will the average person be left out like they will be with PlayStation VR? Or will it be as affordable as previous Nintendo consoles? Speaking of consoles, is this the end of the Nintendo DS era? Or will a new DS release anyway?