Not really. 2.0 x4 is already enough. https://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080_... PCI Express 1.1 x4 is shouting distance within 3.0 x16. 2.0 x4 and 3.0 x16 has no noticeable difference.

And the future is actually less bandwidth requirement:

> Performance doesn't even drop with newer DirectX 12 and Vulkan games, including titles like "DOOM," which are known to utilize virtual texturing ("mega textures," an API feature analogous to Direct3D tiled-resources). If anything, mega textures has reduced the GPU's bandwidth load on the PCI-Express bus.

So: 3.0 x4 will be plenty for the foreseeable future.