I didn't say extremely, just powerful enough there's a decent gap between it and the PS4 and XB1. 

Its extremely safe route and more beneficial for their core audience. The difference between Nintendo trying for the casual market is that we have no reason to believe that they're interested, they've had Wii Fit U, NintendoLand, Wii play, Mario Party, 2D Mario, Mario Kart, Just Dance, Wii sports club etc and clearly they're not that interested in Wii U. Although Wii U is more expensive then WIi, its only $50 more. We should be seeing more of an impact of said titles if the casual market was actually interested by this content, instead the Wii U is selling worse then any Nintendo home console in history. People call the wii a "fad" for a reason, its market was temporary and Nintendo could try and find another gimmick but that is a risk

On the other hand the Gamecube and N64 were "Nintendo versions of Playstation/Xbox" and they performed way better then Wii U, they also managed to appeal to the same broad range of demographics (male/female+young/middle aged) that we're use to seeing with Nintendo consoles, they also had impossible competition (PS1/PS2). Developers no longer hand out exclusives to Playstation like candy as they once did with Final Fantasy, GTA, Tekken, metal gear solid- all the biggest games from the PS1/PS2 era. This presents a clear opportunity for Nintendo to grow provided they build a system many of us would actually want to play big third party games on, this what Microsoft tapped with the Xbox 360. Despite being a Nintendo fan a WIi U could only ever be a secondary console for me, even if it did have third party support I wouldn't want to play games like Witcher 3, Final Fantasy XV and StarWars Battlefront on highly dated hardware, barely better then systems I already have at home (360/PS3)

Going for the core market simply means Nintendo do what they done during NES/SNES/N64 era's and make a few adjustments.
-Release before the competition unlike N64/GC
-Combine impressive hardware with an affordable pricetage just like the above systems (in todays market $349-399 is affordable enough)
-Consult with third parties so hardware works well for them aswell as for Nintendo 1st parties
-sell hardware for profit or take a small loss at launch, offset by launch games.
-release quality 1st party software and make major profits from that
-market themselves in neutral way which doesn't make it seem like they're main demographic is under 12s
-completely drop anything relating to Wii and have Nintendo abbreviated to just "N" in the name just like N64/ NX

Its fall proof, has worked for them in the past and benefits Nintendo fans more as they're more likely to get third party content. Gamecube and N64 had superior third party support and success compared to the Wii U. Hardware is definitely a defining element of this, marketing the other. 

In that case, wouldn't third parties drop the system once the new generation arrived in 2019? I don't believe they'd want to develop a different version for a weaker console, let alone a Nintendo console.

Being casual doesn't mean u need to release a new controller craze every 5 years, casuals just want/need a controller that is easily accessible that they can fully understand after a few minutes of use, something the Wii U Gamepad isn't and the fact that it caused Wii U to launch $100 over the Wii sure didn't help either.

Casuals are also looking for simple yet fun games with new concepts, Wii's later years and Wii U's early years did not offer these, games like Splatoon & Mario Maker are a step in the right direction but too little, too late. Had Wii U launched at $250 with Splatoon & Mario Maker along with a much stronger ad campaign and a better software output consisting of new IP that targeted kids/females/families in addition to their tradtitional IP than they would very likely be in a much better situation, not Wii levels of course but much better than the current situation.

The thing is that "casuals" are always looking for new experiences, simply releasing sequels to those games u listed is not enough, that plus the horrible marketing that left people thinking it was an accessory, the $100 higher price tag at launch (talking about the non gimped sku) and releasing a not so casual friendly controller (Wii Remote was made because traditional controllers had become to intimidating/complex for non long time gamers, the Gamepad went right back to the dual analog, 8 button layout that casuals don't respond to very well). The combination of all these things in addition to Nintendo basically dropping support for Wii in its last 2 years caused Wii U to not be able to hold on to any of the expanded audience they won over with Wii.

Being casual actually does mean you need some kind of new "hook" every few years or the audience loses interest. Casuals are different from hardcore gamers in that way, they'll love Angry Birds for 4 years, but in the 5th year they'll get sick of it and never play it again. And they're cool with that. That's not like hardcore gamers where we like to play Mario, Madden, COD, Halo, for decades on end. 

So Nintendo was actually kinda right about that. The Wiimote was losing it's "wow" factor by 2010 or so. But you just can't "manfacture" a controller phenomenon, it's one of those things that happens once in a blue moon and Nintendo was lucky enough to have stumbled upon it because the Wiimote creator actually went to Sony first and Sony had their own wand controller in development for Eye Toy several years before that to boot. 

Splatoon is not really a casual game. It's a pretty hardcore game ... online only (basically) with a minimal offline mode and very limited local multi. Of course it has the Disney-esque art style over it, but that's just Nintendo's M.O. ... creating deep, actually hardcore game experiences, that are inviting with an initial easy learning curve. But Splatoon is basically Nintendo's first true online-centered game IP. 

So I don't think that would've made a difference with the Wii Sports crowd. Truth be told it's not like Nintendo Land was a terrible game. It's probably the best "casual" game Nintendo's ever made. We confuse "quality" with "market success", the two are not mutually exclusive. 

It helps I think to be able to pull off the "I'm a fan of company X/Y/Z" and just be able to look at things from the POV of other audience bases too. The iPhone changed the world. The world. I don't think I overstate that. The world it changed is one that Nintendo was not prepared for. 

To match what was happening to the casual market with smart devices, Nintendo had to step their game up 5 or 6 fold, problem is they had grown fat and lazy with the Wii's initial success and was in "cruise" mode. When the 3DS did not perform well out of the gate, it was a shock to Nintendo, but really there's nothing they could've done ... Nintendo is just a small fry in the overall ocean to be honest. Apple/Steve Jobs' destiny was simply bigger than theirs. 

Being completely selfish, I do want a Nintendo console with power under the hood, a normal controller, and all the third-party games that a Playstation console receives. It would save me money on buying a Playstation because I would not need it. Alas, that will not happen and I look forward to seeing yet another weak Nintendo console with a controller I don't care for and non-existent third party games that compliment the first party releases.

Ur just making up ur own definitions now, casual does not mean a new crazy "hook" every few years, if that were the case than people would have moved on from iPhone by now. That next sentence is exactly what I'm saying, for casuals u can't just release new hardware that costs $100 more with a couple games that appear to be HD/3D remasters and expect sales to skyrocket, they want affordable hardware, simple controls and new experiences in the software.

Like I said, I don't believe Wii/DS level sales were ever going to happen again but there is a huge middle ground between Wii/DS & Wii U/3DS, if Nintendo played their cards right than they could have been much better off this generation.

This is especially why I say its a risk. Nintendo can look for that next thing but it'll be untested/unproven, thats kinda what they done with the wii U and many of us thought it would be fairly successful (50m) back in 2012. I agree with you that they didn't do enough to carry over the wii audience,  also that the Wii U was executed horribly regardless of its core concepts (I still actually see potential in a tablet controller) but the Wii U is here now so the question is what would be most logical for Nintendo moving forward.

Beyond selfish reasons I think most people suggest  a core system because they can't imagine ways Nintendo could innovate that would capture the imagination of the casual audience. Motion controls alone seem exhausted, VR seems too expensive....Maybe we just lack imagination or maybe theres nothing on the immediate horizon. 

The dockable Tablet console is probably the best thing I've heard thus far.

Apple doesn't have the issues that Nintendo does because they have so much content on their devices. They also successfully understood how to make an electronics brand a fashion statement, something no other company really has been able to contend with, and Nintendo would be so far out of their marketing element even trying to match that level of brand swag. 

Nintendo needs to resort more to singular "home run" type phenonemons otherwise they run out of gas. That's just how it goes for Nintendo. And the Wii was very definitely running out of gas after 2009, the signs were fairly evident long before the ill-fated Wii U, so blaming everything on the Wii U is a bit disingenious. 

Casuals don't need a game console period. If I'm a casual what do I need a $300 game playing device for? Wii Sports/Fit was a fun little fad, but don't confuse two things ... just because a girl wants to dance with you for five minutes doesn't mean she wants to marry you. 

iPhone/Android fans satisfy all the needs of casual gamers in ways Nintendo really couldn't ever compete with. To be honest, there's nothing Nintendo really could've done. The iPhone was just an impending tsunami coming at them that was going to hit them no matter what, and unless they made the iPhone before Apple made it, nothing was really changing that. 

In hindsight there's nothing they could've done. I've had casual friends over to play the Wii U, the ones that basically can't play anything but Wii Sports ... and they had a *great* time with Nintendo Land. The laughter in my house was so loud actually I thought I might get a complaint from my neighbors. But none of them bought the system. Being a quality product just wasn't enough, gaming isn't a "need" for them, sure they like Nintendo Land or Mario, but they like Angry Birds too, but Angry Birds is always with them and is free ... Wii U and Nintendo Land is $350. Not surprising which way casuals went.