No. The architecture remains nearly the same thanks to x86. That is one of the points why PS4 development got significantly easier.
The other machine is just more powerful so you just align the experience to the horsepower that is available.
The situation is similar to every PC game compared to the PS4 version. And don't start with exclusives now. They aren't technically magical things that get more from 1.8TF. The visual fidelity from exclusive titles are mostly because of high production values in the content area.
And maybe, they know exactly what the target machine can do, and tailor the content to fit that exactly, and without being hindered by the PC API's. (This will probably change thanks to DX12 or maybe Vulkan, but the point stands, and even DX12 will still be lacking some console API features, and they are probably addressing this with ShaderModel 6.0.)
The main reason for PC api changes are to better make use of existing silicon which would otherwise be idle, and of course, you still cannot be hardware agnostic:
DirectX 12 Require Different Set of Optimization And Tweaks On AMD And Nvidia Cards