I have playing gregtech now for a while. I am mid way through the tech tree now. For me the major source of frustration was not knowing how to get stuff.
I will give you an example: I want to have a drill as I am used to from IC2. I think hey I have most of the stuff. But then realize that those plates are actually stainless steel. After fighting with NEI for like 30 minutes it dawns on me that this tech has moved way way back in the tech tree.
Another example: I struggle regularly with alloy recipes. Do I need the alloy smelter for this or not. Cupronickel apparently does need it. At least if you are thinking of dusts. But if you are lucky then you notice that cu + ni gives you 6 small piles. I spent like 20 minutes today to figure it out again because I forgot.
This shows the major problem with gregtech. Documentation is absolutly horrible! Most people complain that gregtech is hard because it does not give them what they want. But in reality it simply does not show them how to get it. You have to funnel through outdated documentation and NEI which is simply not made for such complex recipes.
I understand the reason for this. The mod evolves really fast, so it is hard to keep up with documentation.
So here is what we really need: An automated tool that generates the documentation during the mod gets loaded. The mod has to know the recipes of all machines eventually. So why not output this information as html (or even simpler csv) after the mod finished loading. The gretech-tree would be generated by iterating over all gregtech/ic2 machines and tools and looking where in the crafting chain it depends on non workbench recipes. These recipes belong to a machine (the mod knows which one that is) which then itself has serveral dependencies which then either trail of into compleetly vanilla items or hit a non workbench recipe itself. This gives a nice depency tree which also shows the tech levels. The mod has to only hint some small stuff like machine casings so that they appear in the tech tree too.
Since you scan all recipes anyways it might not be to time consuming to add such an export. Others would happily pick up the information and maybe even write an achivement plugin based on this.