Nintendo dont need to rush to put out a new system when there's still much potential for Wii U. I mean who would have thought in the summer of 2013, when the Wii U was at rock bottom that we would have Amiibos for example. We are now talking about Nintendo posting good profits, Amiibo is in its infancy with a possibility of a fully flegded Amiibo game, NFC Pokemon cards could be another option to boost revenue. Then obviously there are more IPs in Nintendos armoury should they choose to keep pumping out great games, Animal crossing, Metroid, paper Mario etc. Nintendo need to make sure the existing fanbase is catered for before moving to the next hardware phase, many come and go, but the hardcore Nintendo fans are the ones that they want to follow, they are the sure thing and the last thing Nintendo want to do is push them towards Microsoft and Sony for being too hasty.

And they won't.. I see the PS4 and X1 lasting a couple of more years than the WiiU! It's not like Nintendo can release the next console before the PS5 and X2 anyway!

And what Nintendo to do to about 2020. with the Wii U when around 2016. they will release all its largest IPs!?

I am 90% sure that the Wii U successor will arrive on the market in 2017. and that the PS4/XboxOne successors will arrive around 2020.

OP is pretty much spot on.

People often forget that units sold isn't the measure of a company's success, anyway. Nintendo, for the most part, have remained an extremely profitable company. They don't sell their consoles at a loss and they make plenty of money off of their published games since they don't have to pay licensing fees to anyone else.

The Wii U's sales haven't exactly gotten huge, but the console is now doing well enough that Nintendo just need to focus on supporting it with some good software. For at least the next year, they've definitely got that covered, and they seem to be building a larger and larger pool of their own development houses as well as nurturing indies, which should keep them sorted for games on the Wii U for a long time.

A successor to the 3DS is probably likely in 2016-2017. I don't think we'll see a follow up to the Wii U until a year or two after that, nor do I think we need it.

The Wii U will make a profit going forward because the cost of production is only going down. The Wii U benefits from the over saturation of the other consoles, when the generation reaches the point where more gamers are looking for console #2 than there are people looking for console #1. The Wii U's lineup in 2014 was pretty damn abysmal, it had two traditional hits and two droughts that completely wrecked sales and momentum.

As long as the games keep coming, sales/profit will only go up. Nintendo has now fixed the major problem with their lack of games so that a drought like that never happens again. They've mastered HD development, learned the magic of outsourcing asset creation, have stepped in to buy up rights to games that have struggled, opened their franchises up to second party development, and expanded their size to make even more games as seen by the creation of a new EAD team.

2015 has more games, and there are still games just as important as Mario Kart and Smash: Zelda and "3D"Mario. People are blinded by Mario Kart because it caught fire with casuals last gen, but every other gen it's pretty much on even footing with or less important than Mario platformers. There's also mid tier games like Star Fox, Metroid, and any of the spinoffs that are coming.

If they had the end of 2014 lineup ready when Mario Kart8 came out their sales never would have died off from that 4 month drought. That situation will not arise again if they get momentum back.

That is not how consoles sales work, sales don't pick up later cause gamers are looking for a second console, GC sales kept declining as the generation went on.

Don't mention games like Metroid or "3D Mario" that haven't even been announced yet and have no proof they are even coming out in 2015, grasping at straws like that devalues your whole point.

It's called s sequel. They happen sometimes. Mario Galaxy 2, another Skyward Sword after Twilight Princess, Prime 1-3, etc.

I hear it's pretty popular.

Why should they hold on to their worst selling console?

It would be a better idea for Nintendo to stop production and development of WiiUs (and its games) and instead develop games for Wii again.

Console Gens work in different ways because of changing times and the Wii U finally has a respectable lineup. It's going up YoY despite have two 4 month droughts. It's only going to be better next year too.

Grasping at straws? Where? They've said they were working  on home console and handheld Metroid and that they're planning a new Mario title. Retro has been working on a "secret" new game since January 2014, and the entire time when people talk about metroid nintendo just laughs it off and says, "Boy we really liked how retro performed with metroid it sure would be nice if we could get them to make another." as Retro is hard at work on a game we don't know the title of.

2013 had droughts too, 2014 had way bigger games coming out, going up YoY literally means nothing, its not impressive in any way, especially when the increase was so low.

Yes you are grasping at straws cause none of that has been confirmed FOR 2015, which is what you said.  You said they are coming out in 2015, show me proof of that.