In tonight's Q&A session following the overall presentation Iwata was asked about the next console. Iwata's reply was that they cannot release a new console until they've satisfied the existing WiiU owners otherwise they'd be similar to SEGA.
Additionally, earlier today Nintendo discussed new hardware in terms of fiscal years and it was clear in that presentation that FY16 or more than likely FY17 was when we'd see something.
Next you have to consider the known games coming. MK8, SSB, Hyrule Warriors, X, Bayonetta2 and many others are this year. Zelda, yarnyoshi, and many others are known already for 2015. Then we have the tease of two major games at this E3... one that will prove soloplayer must-have gamepad use and one based around the new NFP figurines. As well as the mention today that many other games will be announced at E3.
Finally, we also learned today that Wii U hardware on its own is now profitable. Meaning that even at low sales, its still making money on its own even without a single game sale.
What this all means is that Nintendo is not going to abandon a low selling profitable console and risk ruining its relationship with current Nintendo core. Instead they will continue to support the console for a normal life span which is commonly at least 5 years or 2017.
With the current pace of Wii U sell-through, I've been stating I believed we'd see something new in 2015 with a launch in 2016. NOW I am back to the original pre-WiiU launch belief that we won't see a new Nintendo home console until holiday 2017 and it may be shown to world in 2016 at the earliest.
So stop with the redesigned WiiU/gamepad-less design/etc crap. Nintendo is not going to make the same mistake SEGA did and kill of a main console early. It's not going to drop the biggest benefit the console has. Its now setup to make marginal to great profits while it prepares for a normal time frame between generational hardware launches.
EDIT May 13th...
It appears new info is surfacing to prove my point.