Something lost in the Switch reveal is that we are for the first time seeing a Nintendo Console with all available software resources working on it.  Games that may have been bound for a handheld or console are now all in the same place.  The most notable example of this shift is Xenoblade Chronicles 2.  There was a lot of confusion upon its reveal, and a lot of fans are saying "How? XCX was just released a year ago"  The assumption is it's either a long way off, or it's rushed if it's being released in 2017 as stated.  But neither is true.  Way back in 2013 Monolithsoft was recruiting for its 3DS team, for a fantasy adventure.  Concept art was shown on their webpage, and fans speculated as to the type of game:

Four years later we have yet to see the title for 3DS... but we now get XC2 for Switch.  The concept art above seems very much in tune with what we have seen from XC2:  traditional fantasy, a giant tree, riding a creature... It should be clear that the 3DS game changed when Nintendo changed its hardware plans.  So this is probably a game in development for 5+ years in some form.

The story is probably similar in some form for Super Mario Odyssey, which would likely have been bound for the next handheld if they were doing the two system thing.  But it's not limited to 1st party.  Octopath Traveler was shown, and seeing as it's from the Bravely Default team, it almost certainly would also be a handheld oriented title.  But with Swith, it will now be avaialble to home console  owners.

Looking at the lineup overall, you can probably group titles into ones that would have been home games or portable:

Home:  Zelda BotW, Splatoon 2, 1,2 Switch, Arms.

Portable:  SMO, XC2, Octopath Travelers.

If Nintendo was still supporting two systems, you would see those games split.  They would either be still supporting Wii U and launching a handheld, or launching a home console but half the titles would need to be saved for the next DS.

What do you think of this change?

I honestly would have to see year 2 and year 3 to see if the unification was wise move.

I'm getting XC2, but I kinda wish Monolith Soft would work on some new IPs.

I've always wondered why ended up happening o this project...
And I bet you're right given the similarities in style...
I actually got more excited for the Seitch when I stopped thinking of I as the successor to the Wii U and started thinking of it as the successor to the 3DS...
The fact that it's both is no sweat off my back...

Pretty much, you cannot formulate judgement call until you know 2018 really. 

I wonder if Nintendo has any 3DS games left, or if they're fully focused on the Switch.

and in 2018 we cannot formulate judgment until 2019 and so on...

This was Nintendos chance to make us confident that the Switch will have a steady stream of games and they failed.

Nah 2018 it will be pretty easy to formulate droughts caused by Nintendo software has increased or decreased. Year 3 will be painfully obvious on the position of the device and the future of Nintendo. 

That's actually a great explanation as to how Monolith Soft was able to churn out another game so quickly. I guess with a unified library and their increased staff, we can expect a game from them every 2 1/2 to 3 years. I agree that the unified library was Nintendo's only option considering the larger development windows for games and their growing game droughts. Also, when they decided to go the hybrid route, they basically gave themselves no other choice since it essentially locked them out of getting any big budget multiplat 3rd party support, so they needed the unified library to compensate for that.  Furthermore, I think that what we've seen so far during the presentation only accounts for 1 E3's worth of lost games for the last two E3's from EPD alone since they haven't solely developed anything of real significance or complexity since Mario Maker.

Im sure it will be when Super Mario Odyssey and Xenoblade Chronicles 2 is delayed to that year.