i'll throw my 2 cents in, from what i've noticed(i dont keep track) the Moderate mission seem to bring you back more crits, and rare schematics. As example on my slicer i run the mission 'Extinguish The Sun" a Moderate mission and 50% of the time mako returns with Advanced Neural Augmenters, or i can run the rich or bountiful missions for a week straight and be lucky if i get 2 back all week. I was ************ about it one day and a Guildie that has made 500+ million on the GTN pointed it out to me. He says "Try the mission "Extinguish the Sun" it works really well for me" so i did and the first 3/4 times mako came back with 2 augmenters twice and 3 the third time, also came back with augment patterns as well.
Yeah, I never run anything but moderate missions for just this reason. I've found it's not been worthwhile to run anything but moderate missions since The Great Slicing Nerf ages ago. Every few patches I try running higher tiered ones, and the result is always the same - it's just not worth it.