This could be a good thing if they'll only develop new IPs for mobile. It will give them a chance to go nuts and try any ideas no matter how risky or different they are. And if the ship sinks at least there won't be a CD-i Zelda equivalent to remember.

You would think so yet apparently Angry Birds is like the no.1 sellng third party game on the 3DS in the West. 

Puzzles Vs. Dragons sold 1+ million copies on the 3DS in Japan. 

And Minecraft sells like gangbusters on both mobile and home console/PC. 

Not saying you're wrong, but there are also examples to the contrary (even though personally I think paying $30 to play Angry Birds on the 3DS is stupid). 

But all those games are fads. Casual smartphone "gamers" are driven by fads. Nintendo shouldn't have to settle with these kinds of risks.

I don't want to see Kirby Canvas Curse ($4.99) next to Candy Crush ($0) in the app store and people choosing Candy Crush. Neither do I want Nintendo's games to be free to play and then include a bunch of nasty microtransactions. :(

I'm definitely gonna take good care of all my Nintendo handhelds (GB, GBA, DS, 3DS) so that my future kids still have access to quality rather than total shit appz. Hoping for the best regarding NX. A home console and handheld in one capable of running games like the next 3D Super Mario game, a huge Pokémon RPG, Zelda U, XCX, Splatoon, etc.

Stranger things have happened. I think Nintendo is in a really difficult position. They know handheld gaming devices will be obselete eventually so the move to mobile was essential one day. I personally did not expect it this soon though, I thought they would have waited until after the next Nintendo handheld at the very least to move to mobile. Also Sony and Microsoft will most likely get into streaming consoles in the 9th generation(assuming MS does now ditch consoles altogether) and this will give them more of an edge because they can offer the 'console' for cheaper due to the actual hardware more minimal due to most of the visuals being streamed rather than processed by a local GPU etc. Sony is already delving into this with PS Now.

As harsh it sounds its true.

Casual or not, if Nintendo gets people hooked on one and get people to buy into it, then they did their job. Nintendo gets their foot in the door and they will be able to show them other games. High quality games that will get people to talk about Nintendo again. It will be mission accomplished. Who bought a DS for Pokemon but later on discovered tons of other fun games. Same with Nintendogs and Brain Age and the like. It got tons of people into the system, and then the quality games roll in.

There is the potential for this to work.

They have been clear that they will not be bringing their full fledged retail titles to mobile, but rather create new games built with smartphones in mind. People will still need to buy a Nintendo system to play the next 3D Mario, epic Zelda, or Pokemon RPG.
If they can insulate the mobile and dedicated divisions from each other, they could co-exist, like home consoles and handhelds have done since the 80s. Mobile provides additional revenue stream while maintaining awareness of their brands, dedicated systems continue to provide the kind of full fat gaming experiences Nintendo are loved for.

There were concerns when Nintendo ventured into DLC, yet that didn't turn out as bad as many feared. This could be a similar case where the reality is a lot less scary than our expectations.

Can we call the 9th gen. the migration age? Both the XBox and the PlayStation look like they'll become streaming consoles and will offer their services their services trough streaming, and Nintendo will take their chances on the mobile front. Everyone is abandoning dedicated gaming devices and going elsewhere. :(

This could bring Nintendo back to their Wii/DS glory days.

Like your name says, Darwinian evolution.

Survival of the shittest. ;) (Mobile/streaming)