On an unrelated note, I've put together a list of oddities I've noticed in GregTech. I asked about justifications for a few of these a while back in a separate thread, shortly before GT5u came out. Now instead of only being able to work around them with MineTweaker, I can consider trying to make a Pull Request to address some of them. However, first I want to ask again if anyone can provide justification for them, to dissuade me from doing so.
1a. It takes 10 times as much time and EU to smelt steel dust in an EBF compared to smelting wrought iron to get steel (setting aside the time it takes to prepare the wrought iron and oxygen)
1b. It takes almost twice as long and more than twice as much EU to smelt one pile of aluminium dust in an EBF than to smelt three [green] sapphires or three rubies (which will provide enough nuggets for one ingot).
1c. An MV-tier fluid extractor can get liquid aluminium, steel, tungsten, etc. from many different items, including ingots and plates, but even an IV-tier fluid extractor is unable to process the simple dusts (unless the blast furnace requirements are turned off in the config, which also allows smelting the dusts in a simple furnace).
2. Cobaltite ore, which can be smelted directly to cobalt ingots for a tier 3 pickaxe, can be mined with a tier 1 pickaxe, while the Garnierite ore above it in a Nickel mix vein, which smelts to nickel ingots for a tier 2 pickaxe, requires a tier 3 pickaxe to mine.
3. The GT chainsaw shears leaves with apparently no way to turn that feature off, but won't shear vines or sheep. Having the chainsaw double as a branch cutter (when used directly on the leaves) would make more sense to me.
4. Most machine components of a given tier require a specific cable type (with the strange exception of allowing either annealed copper or regular copper cables for MV), instead of allowing any of the appropriate-tier cables to be used. However, the required cable type isn't always the optimum for that tier (e.g. gold cables have higher loss/meter than silver cables, even if they carry more amps), or even the right tier (a ULV machine hull requires lead cables, which carry LV, instead of red alloy cables; an IV machine hull requires tungsten cables, which only carry EV on their own (even if 4 amps), even though osmium and platinum cables carried IV even before graphene cables were given a recipe; an LuV machine hull requires 4x tungsten cables, which carry 16 amps at EV, while several cable types exist that carry LuV: Naquadah, Niobium-Titanium, Vanadium-Gallium, and Yttrium Barium Cuprate; there are currently no cables that directly carry ZPM or UV, but those machine hulls require 4x and 16x osmium cables respectively, which normally only carry IV, instead of using thicker LuV cables or superconductors, or coming up with new cable types to carry ZPM or UV)
6. LuV (tier 6) machine casings require chrome plates, which are much easier to obtain and manufacture than the tungstensteel plates required for IV (tier 5) machine casings (since chrome can be extracted from more common ores and requires fewer processing steps than tungstensteel).
7. Graphite is an allotrope of carbon, yet by default there isn't a simple processing recipe for getting carbon dust from graphite dust (even though ashes, dark ashes, coal dust, and diamond dust can easily be converted to carbon dust)
8. An HV-tier centrifuge or electrolyzer can store 64,000 mB of fluid in the input slot (and presumably also the output slot), but an HV-tier fluid canning machine can only store 48,000 mB of fluid.
9. Multiblock machines have no progress bar to show how close they are to finished with the current operation.
10. What is the point of having double, triple, quadruple, and quintuple ingots and plates? They have lower maximum stack size limits, so there's no storage advantage, and using the triple ingots/plates as intermediate steps for dense plates etc. actually ends up taking more total EU.
11. Many crafting recipes that only use 1 or 2 component types plus hard hammer and/or wrench can also be made in the assembler, but some can't, e.g.: IC2 basic machine casing, some of the casings made from frame boxes and plates, coil blocks, fusion casings, and the upcoming turbine casings.