Nintendo Tablet incoming for 2015 IMO. 

Don't understand the surprise, hardware development has to begin at least 2-2 1/2 years before a product rolls out.

PS4/XB1 were both well in development since 2010/2011.

Seeing 3DS yoy declines and poor Wii U sales has Nintendo probably putting the gas to the pedal with their next hardware.

Development on the next machine begins as soon as the latest one comes to market. It takes years to design these machines. This could easily be the 3DS successor, which probably won't even be announced until 2015 and wouldn't release until 2016.

I agree.  Nintendo needs to put out a really cool nPad Mini to get back the consumers they are losing to Apple.  This next system needs to be a big one.

the word "duh" comes to mind.

If they've already chosen a SoC design/vendor for the machine, a release is probably more imminent than 2016. That would indicate software development can begin probably this year. 

As soon as a console launches, the next one is already being planned; the hardware folk don't take a 4 year holiday.

If Nintendo is smart, they won't release this before a couple AAA software titles are completely polished and ready.  So, I agree, software development should definitely begin this year.  Late 2015/ early 2016 seems likely to me in that case.  That gives a few games roughly two full years of development time.  Luigi's Mansion 3 and 3D Land 2 or whatever the next handheld Mario is.  Those should both be launch titles.

I actually this is going to be a change from previous Nintendo machines ... it won't require specific software for it but will be general "Nintendo game player" in tablet form.

Meaning it'll be able to run ports of 3DS and possibly even certain Wii U games.

Iwata made a comment that kinda foreshadowed this IMO. 

A Nintendo tablet that launches with a catalog of existing Nintendo games like say Super Mario Galaxy, Monster Hunter 4G, Mario Kart 8, and olde legacy games like Super Mario World, Zelda: OoT, etc. ... think of it more of a way for Nintendo to offer their games in a different market/form factor.

That's what I think is happening. Nintendo doesn't have the internal software resources to make three different sets of games for three different hardware but they certianly could go this route. It would also give them an avenue to squeeze more money out of Wii U projects as the system is likely not bringing them the software sale returns they would like. 

I'm seriously convinced that the next thing Nintendo launches will be something that is portable but can stream directly to the tv. It will be high def, more powerful than the wii u, able to be played portably or on the television. 

Here's the specific quote from Mr. Iwata:

"This means that if we manage to integrate our platforms successfully, we may in fact be able to make more platforms. At the moment, we only have our current handheld devices and home consoles because if we tried to make more platforms, our development resources would be spread too thinly. The more we can share software across different platforms, the more development resources will be left for something else."

This is from last year and it to me strongly hints at a third Nintendo pillar which is capable of running some of the same games (if not all the same games) as other Nintendo hardware.