Hi and welcome !
It's hard to say, it will depend mostly on the graphics card manufacturers if they plan on stretching the current 14/16nm out for a few more years or plan on moving to smaller transistors and how those efficient those transistors will be. After the last five years we've discovered that AMD and Nvidia aren't shy of making high-end >250W GPUs, but this generation was much more conservative.
Considering a build with a GTX 1060 and a non-overclocked i5-6600K should remain in between 200 and 250W in most games or tasks, so you're still pretty safe with a 450W. A GTX 1070 should increase the load about 40W if I remember correctly, so consider the reviews with those loads in mind. I believe the Corsair SFX 450W was said to be quieter at lower loads, while the 600W was quieter at higher loads, or noisier vice-versa.