This is one of those things I don't think will ever happen. Especially if things continue as they are now. 

First you must understand that the problem with game streaming isn't bandwidth. It's the hardware running the streams to begin with. 

If you have a global subscriber base of 80M and you even go cheap to make a service that can cater to say 40M of that number at any given time in 1080p@60fps. you simply can't go around having servers capable of running the games for those 40M people. and even at that you will hope and pray that at no given time does 45M ppl try and play games cause that would bring your service to its knees. 

The problem the above presents is this.... let's say each stream is one PS4 sitting in a server room rendering the game for that one user. Who foots the bill for all 40M PS4s? cause if ur service hoes live, and 40M people subscribe with $20/month or whatever. you have to have 40M $200 rendering engines somewhere to handle the load. 

I think streaming will have its place. But I don't think it will ever replace a dedicated console. Another reason for this is that with what they are doing now, a cutting edge dedicated console is always just 3yrs away. And they have the end user pay for that console in full. The stagerred nature of the hardware means people will go for exactly what they want or can afford. With streaming, everyone can pretty much afford $20/month. And everyone will expect it have their games run at the best possible settings. I don't see anyone having the money to replace 10s of millions of hardware units every 3yrs. 

You could play megadrive games on a 32X

Interesting take, I agree with it pretty much... For specific examples, I imagine games with different single/multiplayer modes,
PS4.5 should be able to run the "full feature" resolution/lighting/etc set in the higher performance demand multiplayer mode, for example.
I do expect that this WILL tend to push PS4.0 games into sub-1080p rendering, though...

I wonder if the clock speed is set to ps4 specs if the game runs in ps4 mode, the same as on N3DS.
Letting an optimized console game run with different clock speeds for CPU and GPU requires more testing and can have unexpected side effects. A lot depends on timing, you can't suddenly have some tasks finishing faster than others. Suggesting that it needs a patch seems to confirm that.
(And you can hack the n3ds to unlock the faster cpu speed for older games at your own risk)

Looking through the comments on Eurogamer, NEO has already accomplished 1 thing, succesfully split the usebase.

Yet will they still do as much effort to optimize for the weaker system? Or simply drop the resolution on ps4 and promote the Neo version. Any 900p games coming out on the ps4 from October will be immediate suspects. Could Naughty dog have squeezed out 1080p60 on ps4 with a bit more effort, or did they leave it for the Neo patch...

You call it a best case scenerio, oh this feature is difficult to optimize, let it be for the premium version, no need to spend much effort on it. Basically developers can advertise with the fancy ps4k version and downgrade the ps4 version.

beginning to wonder if some here know what a split userbase even is.......

Stop sensationalizing eveything. Cause you are looking at all this from only one perspective. 

Hopefully it comes out with stock 2TB/4TB HDD. The games will certainly be heavier so I feel like it should be 2TB minimum.

As someone who has yet to pick up a PS4, I'm excited!

Regarding current PS4 optimisation, only time will tell. Its in developers best interest to serve the current userbase. That also will gurantee the best performance (resolution/FPS) out of the Neo version of games. They're not gonna build games around the Neo, just as they don't with High end PCs. Lowest spec/biggest platform will be priority.

I am most intrigued by how developers will take to this and how lengthy/tim consumer the QA will be for Neo.

Its not like we haven't already had PS4 games with questionable performance so going forward may actually be very difficult to tell between what has been compromised by Neo's existence and what would have ran badly regardless (Assassins Creed)

I'm looking at it from a developer perspective. I've been there. Management holding features and improvements back for a later version. Come crunch time, management will take the easy out, deadlines must be met. More versions to test, less time/budget to add features or optimize.

That split userbase comment was a bit uncalled for I admit, was merely trying to convey that opinion is about equally divided.