Keyalha: one thing that makes this mod so much fun is that it is still under development, and will continue to be under development so long as there is a team interested in it. It was about four years ago that I first played. It was a great mod back then, but the progress since then has been phenomenal.
Are there any commercial games that have nearly as much of an immersive and thorough design? I can't think of any.
That is the the good thing about mods. Modding communities keep games allive and make them prosper. When Civ 4 released I would not have even dreamed of the stuff that is in this mod, I would not have dared to even think about a mod this complex and well designed. The amount of polish that went into this mod is through the roof and it shows.