Look to the imagery Clarke portrayed in the Overmind and Overlords. The Overmind as stated in the mini and book is the creator of life in the universe, the cosmic mind of the universe, sending out its plan(aka God). On Earth the plan was interpreted as Religion. As humans evolved the interpretation changed to finally we get the Overlords from Angels to demons, that signaled to the Overmind it was time to harvest humanity. This is where the Brouhaha from the Religious minded comes from, why did Clarke use Christian imagery in the book about the end of the Earth with the Devil working with God to end humanity. The Religious minded will use all manner of deflection to say Clark did not mean it as Christian imagery.
IMO the shorting of the mini a generation does not take away from the meaning of the book, in the mini all of humanity accepts the Overlords with a few dissenting, same as the book. Both in the mini and book the Overlords wanted to get rid of human curiosity and intellect, have just blind faith in the Overminds plan, this through the Overminds helpers the Overlords. (think, the Garden of Eden, live in ignorance with blind faith, or question all with intelligence) When the Overlords first arrived Karellen says it's your choice to do or not to do. (I'm paraphrasing) When in the barn in the mini Karellen was asked by Peretta why have you done this, Karellen answers, you did this to yourselves.
The Meaning(as least to me) is Clarke's asking a what if. What if we got Religion wrong? Would have choosing knowledge saved Earth and humanity?