You guys can see another example in the bit-tech's review of the Define Nano S here:http://www.bit-tech.net/hardware/cases/2016/03/04/fractal-design-define-nano-s-review/3.
According to that review, the GPU (GTX 980 3GB) Delta T inside the EVOLV ITX is only 3 degrees higher than in the Define Nano S and only 1 degree higher than in the NZXT Manta, the latter of which also has a PSU shroud that goes through the entire length of the case. So, Bdonedge, this example strengthen your side of the argument (i.e PSU shroud doesn't necessarily impedes GPU ventilation all that much).
However, according to the same review, the CPU ( i5-4670K at 4GHz) Delta T inside the EVOLV ITX is 15 degrees higher than in the Define Nano S and 17 degreeS higher than in the NZXT Manta.
So, you see Bdonedge, your problem is not the PSU shroud. It's that ill designed platform on top of the PSU shroud that is meant to hold an SSD/pump. It's simply sitting there, right in front of the intake 200mm fan, blocking all the air from reaching the CPU (and to some extant the GPU).
In the end, I have to agree with Gilles3000. A shroud may give the case a cleaner look, but it poops on the feng shui.
Edited by Thunderschnozzl - 6/6/16 at 5:23pm