The Tech Tree screenshots that Old Spider did last summer were useful, for seeing how techs were related to each other, and are still reasonably accurate as to which of the 4 branches to choose when doing a reroll (they are the same as the Focus buttons in the Tech Library, allowing for changes since then).
Most player are used to using Tech Trees from other games, the Tech Library can confuse them, until someone explains how it works.
What confuses people is Techs whose color does not match the filter color, mostly a number of brown engineering techs that appear in the green filter and branch of the Tech Tree.
Personally I would like to see many Techs require two different Techs to be opened up to be researched.
The other thing that confuses them is how the choice of techs that get offered to you to research works. This is very none obvious even to experienced Players who have gotten used to it, and recently (relatively for those of us who started last summer) use the Tech Library.
To me it seems that there is a very strong historical influence on what choices you get offered, i.e. you tend to get offered what you have been researching recently, and not much from areas that you not been doing recently.