I suppose I can make my argument here for why I consider this to fall more into the console space with only some bleed over into the handheld space.  Something of an 80% home console and 20% handheld. 

1) First off, size.  The Switch unit is a bit large for a handheld traditionally. This is common for mobile devices now, the original smartphones were quite small and now they are twice the size. You could look at most consumer electronics that have a screen and see that. The biggest and most distinct feature of a handheld obviously is the high convenience of portability due to being able to slip right into a pocket or a pouch in a handbag, satchel, or purse.  I look at its sized and think look how portable it is.  I see a device that is a gaming device, not a cell phone.  I want it to be bigger than my cell phone and do what they show it does.  I have had a DS in my pocket and that size sucks as well.The Switch really can't in most cases.  There are extremes: the Game Gear was oversized (also failed btw) The gamegear was awesome for its time, and had Nintendo made it it would have sold like hotcakes from their IPs alone. and some people could fit the Switch into those things.  But for most, the Switch unit is large.  And that's before you factor in the Joy-Cons, which are mandatory to use it at all.  Not only do those make it even larger, they also have full analogue sticks that would give you a real issue trying to pocket this or put it in a standard satchel.  I agree that the analog sticks could be a problem, that is why the ones that come as part of them look similar to a DS or PSP controller to meThis is something you will need a more substantial case or to just carry.  Cause it is mostly meant to be portable for short contextual periods or taken to a specific place and setup (airline tray, party table, etc).  Not be available at a moments notice at any time anywhere like handheld. 

2)  Second, it is (apparently) actively cooled.  This also ties into number one cause this seriously changes the convenience of portability.  It means this thing will run at a higher temperature that will make pocketing it unwise for comfort's sake if nothing else, not to mention you would want it to cool and breath.  I understand your argument, but seeing as how your argument is that it doesn't fit in a pocket, how would this really matter?Again, need a carrying case.  Also, the vents and empty(ish) space around the fan area to facilitate cooling compromises the structure.  It will still be plenty strong, but you would definitely not want to subject it to the pressures of a pocket or overly full purse/satchel.  Unlike a handheld which is traditionally pretty dang dense and thus, again, convenient to pocket since it can take those stresses exceptionally well.

3)  Third, handhelds have physical inputs integrated into the device and are not reliant on any peripherals.  It's simple:  handhelds have controls built in, consoles rely on controllers.  The Switch unit is not capable of any use as a system to our knowledge without a controller, either a Joy-Con or the Pro. It seems to me that the controllers that are directly attached to the device, there removability is done for the convenience of the user as an option. This runs directly contrary to handhelds which are built to have literally everything needed to game integrated into a single piece of hardware with no need for aditional physical addons.  Consoles need controllers, handhelds do not.  And the Switch needs controllers. To add to your point, the Switch "pro" style controller will most certainly not come with the system, so its use as a home console with those dinky little controllers right out of the box will be limited. This further proves that it is a handheld.

4)  Fourth, a major distinguishing feature of home consoles is integrated same-system local multiplayer capability.  In short, since handhelds have physical inputs entirely puilt into the device, they cannot support true same-system local multiplayer.  That is, any multiplayer that require simultaneous inputs.  This is the whole reason why golf games found a big audience on handhelds for quite a while, it's one of only a few ways to have any true local multiplayer because of this inherent design limitation of handhelds.  The Switch, obviously, relies on controllers.  And so we see already, it has support for true same-system local multiplayer.  That is, splitscreen.  That's a major distinguishing feature of consoles vs handhelds.   This argument holds almost no material meaning.  The design of switch allows for 2 players to use the device, mostly due to it finally having a really not big enough screen to do so.  Again, a convenience feature that is likely not to be used as much as they would hope or advertise.

For those reasons, I regard this as primarily a home console with mild overlap of handhelds.  People look at this and say "oh it's a handheld that has evolved to somewhat overlap with consoles" when in reality, it is the evolution of this:

That is, it is aiming to be - from launch - a home console that is easily and conveniently portable with the option to play on the go.  And I would say *that* is the word Nintendo is really latching on to:  convenience.  It's literally in every aspect of the design.  The Joy-Cons allowing for local multiplayer with no new controllers, the use of cartridges to allow playing off the physical media for modern games to avoid dealing with installs and get back to plug and play, the size allowing for portability, the battery and integrated screen allowing for playing if there is no TV.  All centered on the original console selling point of convenience.  Will it bridge handheld and consoles for them?  Probably, once they can get a smaller and cheaper version out, it's a bit big and pricey now.  But from a design philosophy perspective, I see a lot of home console design elements here that run contrary to handheld design philosophy.  Basically, just cause you can pick up the core unit and it has a screen doesn't mean it is a handheld, there's more to it than that.

Edit:  Oh, and using mobile tech has nothing to do with a console being handheld or not.  Some mobile tech is used in the Xbone and PS4 as well.  Where the tech comes from doesn't matter, it is the design that matters. Agreed!

Edit 2:  I guess I could say that the Switch is the same thing laptops are to computers, an in between between a true computer and a handheld computer.  Well, back in the day when "handheld computers" weren't just phones :P .  Basically, a device built to give you most if not all functions of a computer in a more portable form while the handheld computers (and now phones and tablets) are their own beast, with the portability aspect being the only thing they kinda share. This continus to be the point from my view.  Nintendo has finally delivered a handheld that has the power to compete against not only other nintendo products, but cell phones and tablets.  It will not compete in the console space unless it gets ports of all or at least most of the most popular multiplats.  Based on the limited memory and cartridge system, that will not happen.

I agree that your theory of design is a good one to go by.  But for every point you make there is a equal but opposite opinion of that element of the design.  To save time retyping your points, I am adding edits to your comments in the text above in BOLD.

Ok, I will direct you to look at my direct response to the first response for most of the refutations or clarifications I can provide, I'm not going to put up another wall of text of that size :P

I will provide some counter points.  For one, the analogue sticks on the Switch are nothing like, say, the Vita.  They are full analogue sticks like on your standard machine, at least as large as the PS4's.  See here:

Those are not going in your pocket or a standard purse or satchel. 

Second, you are using the metrics of all mobiles to go against a handheld device.  For one, handhelds are their own beast (explained in the post I refered you to) and are conventionally pocketable, that was my point.  This one is larger than a phone, considerably, and thicker too.  It's not just uncomfortable like the 3DS XL, pocketing it looks to be physically impossible.  And with the Joy Cons, it is.  Plus, pocketing it with the Joy Cons could damage it, that's a major fail in handheld design.  But as I explained in my other post, this isn't a line in the sand, just a guiding principle that is unwise to depart from for a handheld.

Third, the point of the active cooling is it further compromises the handheld aspect to boost the console aspect.  No handheld - or mobile for that matter - would compromise the integrety of the frame for more performance via active cooling.  Cause that limits where it can be put to a more dedicated or larger bag and adds the issue of heat coming off the device.

Fourth,  I contend the Joy Con's full feature set is most realized in the Grip accessory which almost certainly comes with the console to facilitate livingroom gaming.  They are controllers that can be attatched if need be for the convenience of portable play if desired.  And most importantly, my point was that if you lose your Joy Cons, no more Switch play.  You must have those external peripherals in order to use the device.  A handheld has the whole system as one piece, period.  And plus, if you leave the Joy Cons attached, the portability aspect of handheld design is compromised further.  Again, a console function orriented feature included at the detriment of the handheld functionality. 

  Fifth, the inclusion of same-system integrated multiplayer is a major console feature because adhering to good handheld design - that is, requiring no controllers due to integrated controls and also restricting the size of the system - precludes that feature completely.  Only by violating good handheld design can the system have that feature completely integrated. 

So to conclude, my argument is that, while it has a similar form factor to a tablet or handheld, it has many design decisions that run directly contrary to good handheld design sense.  The size and joy-con design violates the ain of maximum convenience in portability (very convenient for a console, not convenient at all by a handheld or even mobile device standard), the active cooling compromises the internal structural integrity and adds heat to the list of ways the system sacrifices that maximum convenience of portability for more power while also violating the battery-conscious design principle that is important to handhelds and mobiles, the absolute need for (and thus losable) separate peripherals (which again, can't be kept attached to the system while storing in 90% of bags and 100% of pockets and therefore must frequently be attached) violates the all-in-one design principle of handhelds.  And the use of that last decision (need for, inclusion of, and support for multiple external peripherals) to allow same-system multiplayer is a very console-minded decision that comes at the expense of good handheld design. 

Hopefully that plus the other post in response to the other guys response to my first post explains my whole point clearly :P