I'm not truly convinced that Sony has learned their lesson from the PS3, in a large part because (if they listened to their dedicated fanbase rather than the fans they lost) what they believe their mistakes were may be substantially different from what caused them to lose fans.

What I mean by this is that it was the focus on pushing technical features that few people cared about (at the time) that was their mistake, and the high price-tag was a symptom of that mistake. With this in mind I could see Sony pushing for 1080p 3D output under the belief that people will pay $450 for a PS4 rather than $300 for the Wii U because the Wii U only plays the same games with the same visuals at 1080p@30fps (or the XBox 720 plays the same games with the same visuals at 1080p@60fps or 720p 3D) ...

They should release the Ps4 (2014) after the new Xbox (extending PS3 life and try to recover as much money as possible), with a superior (based on devs fully taking advantage of the hardware) system at a reasonable price, with a super Cell, with a faster bluray player, but most importantly with RAMMMMMMMMMM and an up to par GPU (Nvidia if possible to facilitate backwards compatability (lowering the price), even tho AMD would be the better option for consoles GPUs power efficency)

I still think sony will go for power next gen, and I think they need to wait for 2014 onwards to be able to make a big leap with an afordable price (the visual/AI/everything leap will be bigger then alot of people predict).

Last thing I want to add is price, the Vita will be 250, if I had to take a guess I would say that Wii U needs to be between 300 to 400 (and if I had to guess I would say 350), and I say this based on what the controler does, and what the console needs to do to make it a seemless experience. My point is that next generation consoles will not be cheap. The advantage that sony has is the bluray pricing going down, and no need to dump bilions on the Cell tecnolegy this time around, the disadvantage is the amount of money they will have to spend on the GPU.

The better question is, will sony take a huge step forward when it comes to the OS???

My friend's cousin just started work on building PS4's for SONY, so I think Q4 2013/Q3 2014 will be the time frame.

For a significant leap in visuals and gameplay possibilities you need a significant leap in power about 8x is about the average leap in power, the PS3 was closer to 10x (more for the CPU but the GPU lagged a bit). I think arround an 8x leap is the most likely TBH the cost won't be to extravigant because as I have said the extra length of this generation, it is possible that it will also be th biggest leap in power we have ever seen if Sony decides that they want people to buy ultra HD TVs which is possible, the PS3 pushed Blu-Ray and HD because other business interests and they will likely do it again.

While 2x more powerful seems like a large leap logically the actual improvements you get from that in games is actually small. For example Uncharted 4 could look exactly the same as 3 on a sytem that is 2x more poerful but just run at 60fps and I think the number of people willing to invest in a new console for a higher framerate or slightly higher resolution is actually small. And they have already set the precedent that they add more features like new controlers and online features to the PS3 I doubt they could sell the system without a large power leap. 

That's bold of you there buddy

the size of vram for 1080p doesn't have to be 2gb... depends on the quality of texture... and the quantity of texture (objects in the screen that have texture) ... on vita the reason for so much main ram has to do with the OS (example: my smart phone OS and some application in the background use 200+ MBs) and web browsing is also uses a lot of memory. so 128 or 256 was not enough for OS and gaming! in home consoles the leap in memory size will have to happen for obvious reasons but 4 gb for main is a lot IMO... 2 gbs can house the OS with lots of services in memory (audio chat and video chat comes to mind) and still have around 1.2GB or 1.5GB for games...

about the split memory architecture... it will remain like that since main memory is a lot slower, and PC always use this architecture and has never been a issue... the problem with PS3 is that vram is small for the type of games devs want to do... if ps3 would have 512 of vram and the same main, there wouldn't be such a big problem!

but yes... my bet is that will be a 2GB/2GB ram/vram architecture!

I didn't say that you needed 2GB for 1080p I said that there wasn't really a need more than 2GB of VRAM if they don't go past 1080p, I have a 1GB video card and I play all my games at 1080p with AA after all. 

That was exactly my point consoles next gen will have far bigger OSs will offer web browsing (websites are getting bigger all the time with video highres pics etc), crossgame voice chat, the ability to switch between browser and games etc, Stuff like multitasking will take a lot more RAM and I can't see next gen systems not offering multitasking TBH. With streaming technology becoming big in games being able to cache lots of compressed assets loaded into main RAM to be quickly streamed into VRAM will very important next gen. The PS3 having twice as much RAM as the 360 would have of course have been far better, but that doesn't change the fact that for most games 512>256+256. The bottom line is RAM is relatively cheap and for a system that has to be as future proof as possible skimping would be a mistake.

4GB/4GB is possible as well

my English can trick me and readers some times... still imo, it could need more than 2gb... 1080p is 2 mega pixel resolution but devs can put 300, 400, 500, or even 1000 mega pixel of textures in the screen at the same time; and that will go over 2gb of vram... what is needed to be know is if PS4 would handle such size of information. i dont disagree with you on OS size... PS3 have a OS of around 50Mb and i expect it to be 10 times bigger for next gen so 8 times more ram is around what is needed but 16 times more cant hurt for sure!
4gb/4gb is possible i dont doubt ... wasn't the first time that a console would have 16 times more memory that the predecessor.

we will see... can wait for the specs but launch want to be later than sooner!

... really though? 

Even BF3 Ultra will only require 1.5-2GB with it's massive draw distance, ultra high resolution textures etc. With an optomised console system you won't really be using much more than that, you get to the point where adding so much higher textures doesn't really make a difference without upping the resolution. The max texture size on 360 is 8192 x 8192 (PS3 doesn't support full 8Kx8K textures tho)  but I don't think I have heard of more than 4,096 x 4,096 (and even them sparingly) actually being used due to RAM and shading limitations, high end PC games currently go up to 16,384 x 16,384 (1GP) textures as far as I know so I'm not sure 1GP (~3GB each uncompressed not sure now big they would be compressed, I don't know what kind of compression GPUs support) textures will be common next gen. If they did want to go that route (they could if they want another $599+ console at launch) then yes 4GB+ VRAM would be a must and they may want to go for 6GB lol.