The tricky thing about shaders are that they rely a lot on elements passed in by the graphics engine, and if those things are different, or absent, then the shader will not perform as expected (or at all). GameGuru saw the creation of a whole new batch of shaders to reproduce the new visuals required such as multi-textured terrain, cascade shadows, different shader techniques for quality levels, and of course, the post process shader which has seen the addition of motion blur, depth of field, adaptive bloom and most recently SAO.
My advice would be to take the new GameGuru shaders and tweak those, much like you did back in the day, to achieve the additional visual effects you are after for your games. Just make sure you back them up as when GameGuru auto-updates via Steam, those shader changes are overwritten with the official ones so giving them new names and placing them in a new folder is a good idea.
PC SPECS: Windows 8.1 Pro 64-bit, Intel Core i7-5930K (PASSMARK:13645), NVIDIA Geforce GTX 980 GPU (PASSMARK:9762) , 32GB RAM