The change to Catherine Summon (being able to use ET stance) wasn't made by players on Discord, it was something that I planned from the beginning and it has worked out in rGE very well. I don't know about the consumption of materials, what we have for catherine, Jack, Diego and Angie stances is official behaviour.
I have already refused a suggestion about changing those materials for a very particular reason: It ruins the mini-economy around Cast Iron and other similiar items. The decision hasn't been changed.
If anything those construction characters would need a complete overhaul, changing the material consumption doesn't change anything.