I loaded your mod with an existing game to check it out and it loads in with default 40 qualities and 0.2 chance of increased quality. This feels way too easy and even overpowered hahah.

In my savegame i just landed on Fulgora (another playthrough im doing :p) I Just unlocked quality 2 modules... and barely had a few plain modules. and i already see Quality 4 and 5 (uncommon, which is similar to without the mod legendary!! hahah) already flying around omg... so that 0.2 chance is really too high.. or... it is something with the chance from plain to get something 5 steps up? that was almost an impossibility in vanilla...

other than that this mod looks awesome! I am in the works figuring out a next playthough with it and dig into it. but with 0.1 or mayb even lower lol else ill fly through it too fast as quality junky :D