rework materials from the ground up

[Sundance]

bring back the additive barrel

No.
Materials should be research in it's own right, and not effected by chemistry. Adding chemistry into it did the following:
A) Unbalanced it terribly
and
B) Made another system rely on chemistry.
and
C) Neglected everything else with materials.
This lies with the inherent issues of my second point above: "Many unique properties/properties of materials are boring as heck." Something that is fun with chemistry could be applied to various ores/materials properties, but leave chemistry to the chemists.