"As a player, I want to have a clearer display of the technologies' dependencies so that I can see in a second what technologies I need to research to unlock what I want" (I'm not great at writing user stories, sorry if it's not clear enough)
To better illustrate what I mean, here is a part of the Civilization V technology tree :

The added value is user-friendliness. For experienced player, this would maybe be inconsequent, but it would lower the barrier of entry for new players, without changing anything to the game mechanics (I say this as a new player)
I'm sorry if this has been proposed before, I tried to find something similar in the forum and didn't.