[Suggestion] IC2 Shafts as expensive material
In some versions of IC2 and related versions of GregTech, there were Iron and Steel Shafts as items, obtained through extruding a Block of Iron and Steel respectively.
I was thinking that Shafts of various materials could be a great addition to GTCE as an expensive, slow-to-process material, similar to Dense Plates, to use with / instead of Long Rods for high-tier Assembly Line recipes, by example.
I personally think keeping the basic recipe of Extruding a block identical, but expanding it to more materials using GTCE's architecture, is the best option.
In general I don't think it is a good idea to add items to base GTCE just on the off-chance they might be used in a modpack.
But you can do it yourself by writing an addon mod.
Or you can use a helper mod like: https://www.curseforge.com/minecraft/mc-mods/devtech example configs: https://github.com/idcppl/DevTech/tree/master/examples/
Or for simpler items than GTCE's metaitems: https://www.curseforge.com/minecraft/mc-mods/contenttweaker
Recipes can be added/changed using crafttweaker: https://docs.blamejared.com/1.12/en/Mods/GregTechCE/Machines
And you can even define your own multiblocks: https://www.curseforge.com/minecraft/mc-mods/multiblocktweaker