The invariant of Civ games is that they need to create an immersive experience related to the historic period you are in and around each civilization.

Commercial Civ games achieve this using a combination of graphics, music and sound effects. So I think the challenge for FreeCiv is that, is to become more immersive in this way.

e.g: In commercial games you have accompanying music, you have sound effects and unit sounds for each language, each period looks very distinctive from each other.

But don't get me wrong though, I think it is a fantastic project, and have had fun playing it over the years. Same with FreeCol.