Ok, but do you really think PS5 will be realeased in late 2020? I just think that SONY will prefer to announce early 2019 and release late 2019. I'm not saying that because I want to see a next gen console as early as possible. I just think 2019 is a good year because SONY already said they will analyze their profitability and plan new projects starting in 2021. So starting a next gen console late 2019 is something similar to what happened with this current gen in late 2013. This gen began in 2014 from the marketing point of view. Another thing that makes me think that late 2019 is a good year for PS5 is something called rumors. They are getting more popular and that happens in all generations when we're approaching to the end of them. Next year AMD will realease NAVI 7nm(The next gen GPU). The project Erebus was recently found in codes of Unreal Engine. Developers are making a lot of damage control saying that it was a misconception. But we all know that SONY usually includes Mythological names in their projects. Erebus, in Greek mythology, is the fifth god to be created. The amazing and unbelieveble graphics that have been shown at E3 are at least one step forward from everything we can imagine running in a simple PS4,PS4 PRO.

In the worst case I could expect these games running in the both generations. Repeating the same crossgen marketing made with The Last of Us, Watch Dogs, GTA V, Destiny and others. We have a lot of clues to believe that PS5 will hit the market in late 2019.
So I think the specs below will be plausible:
NAVI 7nm with 10Tflops
8-Core Ryzen 3.2Ghz/First or Second Generation
16 GDDR6
1TB HDD
UHD Blu-Ray disc for $499 or disc less for $399.