Look, I'm not trying to rain on your parade - just pointing out that the suggestion for new controller types simply boils down to getting more for less. In this case less internal space, less power, less mass etc. And actually... I'm not against that - for example I hate it that the universal controller comes with 125/140T for what could essentially be a chip.
I don't quite understand from which words you concluded that it would be so ? I played some TES a long time ago, I don't remember the exact version. There, when you reach the level of a mage (in the elite it is the discovery of a special engineer) you can invent your own magic. But there was well thought out balance. If I want it to hurt, then it will eat up a lot of mana.
So I wrote and here you open this engineer and modification to drones must collect a VERY large amount of all sorts of materials and cost it will be very expensive.
And in addition there will be a balance if you make the modification better existing it will weigh more and eat more. BALANCE.
Why do you think that the droid builder will be without balance?
Where did I say that?