It would be nice to have upgrades for the machines. It could be tiered like the hardened-resonant from TE. But i thought it would be nice to have a few upgrades slots like 3-5 standard. The content of the upgrades i thought of are:

• A base upgrade plate doesnt do anything, crafting item only
• A speed upgrade of course
• A expansion upgrade, it will increase the number of recipes that can be locked in a combiner at once. if you go with 5 upgrades slots in a machine i think every expansion upgrade you insert will unlock 1-3 slots.
• A efficiency upgrade costs less power per action
• A upgrade that unlocks certain recipes

I think every upgrade needs its cost. So i thought of a few:

• base upgrade plate should be available when you have access to steel (early-midgame)

• speed upgrade should be exponentially costing power

• expansion upgrade every slot should half the processing speed. Because otherwise people are just gonna put the same recipe in twice

• efficiency upgrade wont decrease processing speed but should be expensive to make and only a certain amount can be added to the machine's upgrade slots