Yes, Metal minds and Primer Cubes. Typically, I like to think of something as complicated as a modern combustion engine: many small Investiture techs working in concert to achieve a greater and more intricate action. Things like construction equipment, modern weaponry, and home appliances. But it keeps cycling back to the same problem; is Investiture all that great of a fuel? Is it common enough to be used everyday? And is the work it accomplishes as efficient or as powerful?
Magic can accomplish things with greater ease. But it is also much less available in the hands of common man. In order to get Allomancy to a normal person, we need Primer Cubes. In order to get Feruchemy to someone, we need unkeyed metalminds. Unless you want to use Hemalurgy...
My point being, perhaps the technological age we seek for Scadrial is not as magic centric as we hoped. Perhaps only certain technologies can be enhanced by magic systems, and they build these more complicated and rarer systems on the backs of normal processes. We saw a lot of this in the second era, where guns and electricity were fairly common, but coinshots were still relatively rare. Are you seeing my point?
A way out of this that I can see with minimal damage involves hemalurgic compounders. Men and women who gain a spike to make dozens of unkeyed metalminds and charge Primer Cubes to help the common folk. Hemalurgic compounding would be a great benefit; imagine strike teams, each with metalminds containing speed, strength, mental thought, and other attributes. An era 4 military of incredible power.
I am wandering now. But the ideas continue to flow! Each man has a "survival pack" with a full unkeyed metalmind of each attribute that can keep him alive when he is in danger. What happens when each Scadrial soldier has a Band of Mourning? And it all comes from the Hemalurgic Compounders.
I know I totally got distracted. Then again, this conversation is "Rambling about technology in era 4". But still, what are all of your thoughts?
The Ultimate Archivist