The modification/application of the new "Normal" texture, I think generated a relative drop in the quality of the graphic effects of shine and reflections of metals. That old known issue with the new .DDS Normals.
And as for the diffuse texture, this texture remains with the same low quality, you just increased the resolution, which doesn't improve the sharpness as the pixels will be "broken". And in fact, the original texture is very small in the human pack_armor model. Our friend Vulfar gave a tip, to use the "preserve quality" feature, one of the tools of the current PSP, but it didn't have much effect. We needed the original texture of the isolated shield and that, I believe that only Blizzard has it, not even the most archaic patches of Reforged you will find this Footman.
Ps. The shield (as for the polygonal ones) is also a little square, I think it should be longer, according to what it looks like in the BlizzCon2018 videos.