In an attempt to fix the overly bright metallics brought about by the Saint of Altra patch, Hotfix 25.7.4's metallic fix came with some unintended side effects. Materials that are supposed to be matte/non-metallic now reflect alot more light than they should. I'll review some examples below.
(All 'Before' pictures were taken prior to Saint of Altra update, using the exact same graphics settings for both images. No ReShade/SweetFX/ENB graphic injections were used, everything is purely vanilla. Colors used for frames also remain unchanged in both pictures.)
Let's start with Volt and his Amethyst skin, which is mostly based on his default skin. This material in particular (mainly for his legs) is actually supposed to be glossy, but the shader change in the Hotfix somehow distorted the reflections and made it rougher and more intense.
Mesa Prime had a distinctively leather-like material for her Prime skin, however after the Hotfix it made it look alot more oily with the new reflections showing.
Tennogens and armor pieces are also affected, with skins such Ivara Astrea and the Saturn Six Armor losing their matte finish. Ivara Astrea's torso and lower body area (colored black) was supposed to have a brushed and the shoulder region (colored purple) was supposed to have a rubbery-matte finish. Her head is the only thing not dramatically changed.
Despite the metallic fixes, it seems some metallics still remain really bright as well. Tennogens like Mag Ferro and Oberon Blade of the Lotus (not shown here) still have quite bright metallics, in addition to a more reflective torso despite it supposed to being a rubber-cloth-like material. (Also you might notice everything seems alot brighter in the Current patch, despite both pictures having Adaptive Exposure turned on and Brightness/Contrast at 50/50. Starting to see a pattern here?)
And these examples are just the tip of the iceberg. Almost every frame I look at have their specularity dialed up to 11, and it is especially noticeable for Gauss because he looks very chrome now, as opposed to his original brushed metallic look. Pictures of Gauss and a few more frames can be found here.
I would believe that these alterations are intentional if it was only on a very select few frames, but this is nearly everywhere. Default, Prime, Deluxe, Tennogen skins are affected, with similar levels of specularity among them. My guess is that the problem is not so much with the textures and the specular maps of the frames itself, but rather caused by the new lighting system in combination with the added shader change in the Hotfix, which is very overexposed and causes alot of problems with the Adaptive Exposure graphics settings.
Notice how in Volt's comparison pictures, the background colors are quite different? That is actually the exact same background color used in Color Key Scene, and both pictures had Adaptive Exposure settings off as Color Key Scene is too dark with it on. The new lighting also slightly changes the tint to be a bit greenish in these scenes, despite Color Correction being on in both pictures. I might cover more about the interaction between the new lighting & rendering tech and the Adaptive Exposure settings in another post, should this problem persist in the future.
I won't lie, some metallic surfaces actually see some improvement and it seems that the landing craft Prisma skins had their original looks restored, if not made better. But it does come at the cost of other materials that each have their own unique character and flavor given to them by their roughness. I appreciate Steve and his team's efforts to continually improve the rendering technology of Warframe, but unless a better solution can be achieved that returns the original materials' look, I think it would be better to postpone this upgrade and resort to the older rendering tech for the meantime.