Hi,
I agree with this, with respect. But I mean if there's a limit of printed fuel, we will focus on make more-efficient drones, not make more of them. Now, we only need to produce enough amount of killing drones and you can finish the mission, right? We do not need to optimize our production, preventing if from cold and hot, making it faster to get across the earth...
If fuel is limited, we can only produce several drones(stop produce after the timer is due). I think it will make us focus on how to optimize them. I believe this limit will not kill creativity, but to encourage us to make us think more, and do it better.
For sandbox mode, i think that there should not be any limits, anyway.