Random idea from someone without Space Age access ATM:
Increase any machine's Module Slots by the Quality Number. So a Legendary T3 Assembler has 9 module slots, and a cryoplant gets 13.

This makes sense, and is undoubtedly balanced and not overpowered at all.

As all suggestions by those unburdened by knowledge of what they're talking about, feel free to tell me it's impossible.

Yes, I would like the idea to increase module slots, but a lower number would be much better, not that OP, like +10% for every level, except legendary gives +20% (normal rounding rules applied, so from 0.5 is rounded up, otherwise down), this means +50% module slots, so Q5 T3 Assembler has 6 slots.

This will be an optional feature in a later version of the fork.