If the textures have standard naming conventions (like Gun_Normal and handgun_Albedo) you could easily create a script that will execute certain actions based on the texture you are currently processing,but yeah Substance Designer's approach is really the best way to batch tweak a large amount of textures.
Frankly,I never liked the "traditional" workflow of Photoshop,and the only time i use it for texturing is to create actions/scripts that will automate the process of everything that i think should be automatic,like creating a Curvature from a Normal Map and generating scratches based on the convexity and dust based on…