Having an unified console would be bad because the handheld would hold back the console spec wise and the console would limit the functionalities for the handheld. The price for such a device would be way too much.

Having too devices that can play the same games NX handheld and NX console would be a disaster financially speaking, most of the money is made from games and I don't think Nintendo is looking forward to having their total software sold cut by half.

In a post before I showed how the majority of Nintendo published Wii U games are under 8gb and all but 1 or 2 are under 16gb. So 4-16gb games cards would be sufficient for most with a few exceptions using 32gb cards.

Their software sales would likely actually rise not drop. 

Pretty much all of MK8, Mario 3D World, Bayonetta 2, Pikmin 3 Hyrule Warriors, Splatoon, etc. would sell 50-100% more if they actually had access to much larger 3DS buyer base than being stuck on the rotting, tiny Wii U userbase alone. 

DKC: TF is a very obvious victim of the Wii U ... that game really should be 3-4 million seller just like Luigi's Mansion 2 is on 3DS. 

Instead of having to make redundant software like Mario 3D Land and Mario 3D World for instance, they could do something like Mario 3D World followed by Mario Galaxy 3 instead too. 

But not for third parties, so it would be another wiiu? 

It be another Nintendo...

It's nothing specific to Nintendo, but I think making a unified portable & console platform would be a huge mistake.

It's a universal mistake among engineering companies. Unifying platforms and systems, almost never works out. Everybody thinks hey, rather than support both System A and System B, let's make System C which unifies them.

More often than not, this ends up as C not really replacing A & B completely, thereby C adds complexity overall, and the company has to divide it's resources supporting all three A, B, C.

I guess it`d be cool if the console feel can be taken on the go with the handheld part. It`s gotta be affordable first though.

A $200-250 handheld in 2016/2017 can realistically match Wii U level visuals along with a 2-3x more powerful console variant for a similar price. Games that scale to/from each device at different graphical settings is possible between such devices.

Why would they lose money on games? It frees up people to buy more games if they don't necessarily need two seperate devices to get the full Nintendo experience.

No longer would Nintnedo need to develop 2 seperate Mario Kart games, they can just make one that runs on either device. After that, the team can move on and make a brand new game, perhaps revive F-Zero or something while also supporting Mario Kart with DLC in the meantime.

The best benefit for Nintendo is that certain games aren't going to underperform just because of the hardware they are on. Tropical Freeze has sold about 1 million, lifetime it may sell closer to 2 million, if it was available on both 3DS & Wii U, it would likely be a 5 million seller like previous installments. Same goes for Mario 3D World, it has sold pretty well, might be around 5 million when all is said and done but if it had the 3DS install base to sell to as well, it would probably sell over 10 million.

So in this scenario, each individual title has a higher chance of selling well with Nintendo also having the ability to branch out more and make new ip at a faster rate which increases their chances of finding the next big Pokemon/Skylanders/Minecraft craze among kids.

Yeah look at how terrible these products are selling:

Can Nintendo even realistically support a PS4 level hardware ... while still making seperate Vita+ level handheld games and smartphone games?

IMO the answer is a resounding NO to begin with.

They can't even deliver an HD Zelda in under 4 years of development.

How the fuck is the next super-duper Zelda PS4-level gonna work under this Nintendo fan fantasy? 7-8 year dev cycle?

People are not happy with the Wii U/3DS release schedules as is. 

Like I said unless Nintendo wants to hire 2000 new people (which they will never do) Fusion may be less a choice and more of the only viable way Nintendo can have multiple hardware models going forward, unless you want zero improvement in visual/design fidelity.