As most of s know, one screen is not the other, and to be quite frankly our HD TV's are going to be outdated, we have a knew spec called rec 2020 coming up. Furthermore with the birth of UHD TV's and UHD Blu ray 4:4:4 croma sampling is finally becoming something that is possible for 4K tv's at least to process and display. Finally HDR and 10 bit colour will become the standard eventually. Unfortunatly the consoles of today don't care for these new features and the PS4 wouldn't even be able to transfer 4:4:4 chroma data, neither is it able to send 10 bit colour if it wished to. In the video below 4:4:4 sampling is further explained, even blu rays today use 4:2:0 unfortunatly.

Lately we have rumours of a stronger PS4 a PS4.5 while I think upscaling 1080p to 3840x2160 is BS on a console, tv's handle that just fine as it is. The other features which are coming along with UHD like HDR, 10 bit colour and 4:4:4 sampling can be of added value. The former standards need to be supported on PS5 at the very least since it produces a more natural looking picture. The problem with this is, that it will probably take a bit of horsepower to actually transfer this kind of data. First of all the PS4.5/PS5 needs to support HDMI 2.0(a), secondly the PS4.5/PS5 need to support HDR as non HDR content on the same disc, ultra blu ray is already doing this and a simple twitch in the menu should do the trick. As for 10 bit colour/rec 2020/p3 standard, you tv either supports it or it doesn't but if it does (1024 x1024 x 1024 10 bit) 1 billion colours are better than only (256 x 256 x256 8 bit) 16 million  colours. Consoles will never be able to compete with pc's but by implementing features like these, they are going to get sharper, brighter images with way more shadow detail at a presumably low cost of horsepower. Now unfortunatly it's going to take a year or three before all these standards are available for the regular costumer (let's say within the samsung 7000 tv range). But wouldn't it be very unfortunate for a PS5 of PS4.5 to stay stuk in the rec 790 era which is the benchmark for hdtv's while screen technology has passed way beyond that.

The final piece of the puzzle includes that the PS5 or PS4.5 is going to support HVEC or H.265 to actually be able to send these signals, if the PS4.5 does all the above it has a new key feature. This key feature is that the damn thing is able to play UHD Blu ray with all it's content. Now why would Sony want that, well this is very simple the PS2 and PS3 showed us that supporting the newest optical discs is somewhat of a selling point, because why buy a UHD Blu ray player for €400 when you can buy a console and UHD player for €600- which supports plenty of new features in games, due to extra horsepower like HDR. This way PS4 games themselves are maximized on PS4.5 and PS4 and obviously the things standing above need to be standard on PS5.  

I have a lot of doubt that physical media will exist in the next gen of consoles (except Nintendo's) and I would actually be rather disappointed if they wasted the money and effort to put a player in the next gen. UHD is far too niche at this point to bother with for a mainstream console, not to mention the horsepower to drive such a display for games in a console is a long way off (at least at affordable power efficient levels).

That's exactly why I want 10 bit colour, 4:4:4 and HDR. You can still enjoy these features if they are being rendered at 1080p. Besides a game can be not physical and still suports these features. On the other hand next gen games will probably still use discs considering they are nott going to put a 5TB hard disc in it. And when your internet isn't very fast 50GB is a long install time to hook up a game you previously deleted due to storage space. The pricing on PSN alone is enough reason I don't want optic discs to go. In about a year or three most tv's will be 4k tv's already, even the samsung 6000 series is already mostly 4k. But supporting 4k resolution is to heavy for consoles, but to suppport HDR, 10 bit colour and 4:4:4 should be quite doable a GTX970 supports 4:4:4 already and in 2020 that card is probably outdated. 

I'd say this year is like what 2004 was for HD. UHD TVs are now at mainstream prices and being pushed in all electronic stores. Theres a lack of content which means that people don't necessarily have a reason to pay that extra few 100 dollards to get the 4k TV over the 1080p one, but the transition to shops selling mostly 4k TVs will happen in the next few years. it only took a few years for 720p screens above the size of 30" to become extinct. Any console arriving in the next few years will be early for UHD but  certainly not too early. Being capable of 4k doesn't all games  will aim for it, it partially comes with the territory of more powerful hardware. Numerous PS3 games failed to hit 720p, let alone the 1080p the console was capable of.

UHD bluray is partially dead on arrival but I don't think it'll be that costly an endevour (its just a 3 layer BR disc) so PS5 will likely support it if it hasn't abandoned discs (it probably won't, digital is still not close to 50% of software purchases yet)

A few people are probably on the side of Sony releasing a PS4.5 but where do they ensure customers value in the consoles that they may have just purchased. It's not like Sony is subsidizing the upgrade at all like the cell phone carriers do.

How fast is a 10bit colour panel though atm? do UHD tv have them already?

Gamers demanded faster ms so they created 6bit panels for it to get it down to liek 1/2ms because 8bit was too slow and had ghosting.

let my discs being read from the blueray player in order to save space on the harddrive

There are a few 10bit panels out there to expensive yet for me (Samsung S9000 series), the in put lag on tv's is in general higher than the one on monitors. At this moment however HDMI 2.0(a) is able to transfer 10bit UHD HDR 4:4:4 at 60fps at this moment at a huge banwith. But with today's octacore and quadcore processors in tv's even that is a matter of time. For instance the first 4k UHD TV's had much higher input lag than those being made in 2016, but with the continual improving processors in tv that can be solved pretty quickly. Otherwise you can give gamers choices in the user menu, I would gladly sacrafice some input lag in SP games for better color and contrast reproduction while in MP I want to have minimal input lag. 

Yeah I didn't get that one either, the installing isn't that bad though, but at least make sure the patch files are safed somewhere else, so that I am able to just delete the game, while I keep the patches. Installing a game on PS4 takes only a few seconds downloading all those patches an eternity.

In all honesty... I would rather just see a really cheap slim version of the normal PS4.