Market their products better. Focus more on the console rather than the controller. And as the handsome man Kotastic said, "not to use their previous brands' name." I've always believed that marketing was the Wii U's only problem, most casual players and parents must think it's a $250 Wii add-on to go with the rest. When it's actually the console that the Wii should have been.

A system's power means nothing, don't let the Internet make you think otherwise, the Wii proved that, you don't need HD, generic FPS games, or Jack Tretton to tell you what to play in order to sell the product. The Wii was marketed brilliantly, to the point where there were even oldies in retirement homes playing them, and it had nowhere near the power that the PS3 and 360 had. No HD, no trophies/achievements, no social crap, and laggy online, yet more people bought it than the other stronger and technically superior consoles.

There are 3rd party games on the Wii U, but no-one bought them, even looking at their pages on Miiverse no-one plays them, there's no audience. It's not Nintendo's doing. The people who bought the Wii U did so to play Nintendo's 1st party content. There's enough consoles out there that have the same games on them. A guy on here said it best, it's not a charity, I'll buy games that interest me. It's up to the developers to do that.

that to not name anything Wii("") anymore. People do care about console power especially developers. and finally there is a thing called marketing/advertisement. I still to this day have parents asking my why should they buy the wiiU controller add on for their wii lol

What they should have learned, summed in one sentence:
Define your target audience and then design the right product for them, rather than design a product and then find an audience for it.
Have they learned? we'll see in a couple of years.

I hope they learned don't trust EA.

If Nintendo follows through with "Fusion" as most expect, their HH  power by default has to "move toward the middle", to satisfy Ninty's home con. fanbase.  Of course, that means the Fusion home ver. will seem optional and not much more powerful than the HH.  I'd predict the home ver. to be equal with the HH in power, but the only reason I have hope for a higher spec home model is from seeing the Smash bros U direct, where Nintendo was touting the visual difference vs the 3ds :

 
My mind was blown when they showed this graphic.  So Nintendo might want to use the extra power as a selling point for the home con.  Wii U level power for the HH would be much higher than their original type of leap (which would be slightly more than Vita).  But I expect the home ver. to still be weaker than XB1.  

I think if they go with the unified concept, the handheld will be somewhere between Vita & Wii U in terms of power, being able to handle Wii U level visuals on a small screen and lower resolution, similar to the way 3DS is between PSP & Wii. The console will be a slight upgrade from Wii U, similar to the way Wii was a slight upgrade from GC.

These devices will share the same architecture, operating system and online infrastructure so that all games can be played on either device, just at different resolutions/graphics settings.

1) How important the name of a console is. Bayonetta 2 special edition comes with a box on the back explaining how you can't play the game on Wii. That's two years after launch. There is no such confusion with the other consoles.

2) Without a successful gimmick to lure a more casual market into a purchase, any Nintendo console going forward is pretty much guaranteed to be in last place with very modest sales. So future hardware should be designed with profitability at the forefront.

3) They have to rely on themselves for software. Keep producing high quality games and make even more third party deals. Maybe buy a studio or two.

That Cranky Kong is AWESOME!

That the gamer nowadays don´t demand great videogames, just hype.

While I don't think Nintendo cares too much about gfx fidelity, I do think they'll want to improve on what their devs can apply in terms of visual effects.  For optimizing Nintendo's trademark "toon" visuals, they might want their home con. games to run 1080/60 with AA (won't nec. apply for Metroid, or realistic Zelda, etc).  

So I'm not exactly sure how much power Nintendo would need to achieve a visual leap that would be to their satisfaction, but I imagine somewhere around 800 gflops to 1 tflop or shy of XB1.  If the home con. is negligibly stronger than HH, it runs the risk of being purely optional.  Just like that graphic I posted w/Nintendo touting the visual difference from 3DS vs Wii U, I do think Nintendo will find the right balance to make the home ver. a lucrative purchase.  By combining architecture and (assuming) game library, to regain that lost stream of game revenue Nintendo will want/nudge their consumers to "double dip" on HW, so gamers can play their games everywhere, on the go or the traditional large screen presentation.