A lot of this discussion is missing the most important component of these builds...pricing based on business strategy. Ryan has already talked about moving gamers over from current gen asap. Sony has 100 million PS4s and their business relies heavily on a traditional model right now. They need to thread the needle more carefully than Microsoft who has less of a base to transition and who's growth will rely on Lockhart, Cloud and PC. Microsoft doesn't lose as much having a top end model sitting on their show floor that only sells to enthusiasts due to it's cost.
Next gen will be defined by the CPUs and I/O speed. This is why I'm 100% in favor of Lockhart. CPUs and I/O speed is why next gen is exciting. It's why we'll get new experiences and different game design. GPU will net you increased resolution, bells and whistles...scalable stuff. 8Tflops with a Zen CPU will get you 4K/60 and no load times with an option to trade resolution for more visual effects. Casual market will not notice the difference between an 8tflop image and a 12tflop image. Hell...I'm betting most of the enthusiasts won't notice outside of side by sides considering resolution won't be a factor the way a 40% GPU difference got you from 900P to 1080P in 2013. The PC market has grown this past gen because that's where the image enthusiasts have gone. Getting into a tflop pissing match on the console side is dumb for the market leader.
A less eccentric design also allows Sony to have full backwards compatibility without any magic on the software side as Shpeshal Ed mentioned.
Bottom line is if Sony is able to achieve a $400 console at 8TF with standard memory, they should do that. From a business standpoint, I can't see any excuse to miss a $400 price point if it's possible considering they have 100 million gamers they want to move asap.
