Class mods in this game have insane variety and getting a perfect one with the stats you want is insanely difficulty.
My suggestion is to implement some kind of grinder that you can feed mods of a specific type (for example, you feed it executor legendary com) and get one point for each. After you have x points, you can consume them to generate a class mod of the same type with a stat of your choice and two random others. Similarly, if you have 2*x points, you get to choose 2 stats and have the last one random. We can stop here or even get 3 guaranteed stats for even more points, but this is a design decision.
We can have something similar for guns. For example, sacrifice x guns of the same type to craft one of that type with a random anointment or a specific anointment.
This would reduce the insane pointless grind of killing a boss 1000 times. I mean, killing it a few tens of times is ok, but how do you justify killing a boss 7000+ times to get a class mod with perfect stats?