At least on the current Android version of the game, the encyclopedia leaves a lot to be desired... Some obvious improvements that come to mind are:
Sorting, tags, etc.
Buildings, techs, etc. grouped into categories of some kind.
Clickable dependencies that take you to the entry for that item (resource, building, tech, etc.)
These may all be implemented in desktop versions of the game. I haven't tried those yet so I don't know.