For those of you having problems with the "Waiting for other civilizations", this is a BTS bug and not limited to RFC. It's only happened to me twice, but I found that I could quit the game, reload my save, and the next time it worked properly.
And one more thing I noticed. If you think your computer is stuck at "Waiting for other civilizations", try to move your mouse and scroll around the map. I've found that if you can't scroll (you usually can't scroll in between turns), it means the machine is actually still processing the turn, whereas if you are able to scroll around, something has messed up and you shouldn't wait for it.
And, since someone mentioned the Byzantines (Romans?) collapsing. It seems the one thing that takes RFC the longest to process (well BTS too, but the RFC map is so much bigger than I usually play) is recalculating all the borders and trade routes whenever borders expand, cities are captured, or boats perform a naval blockade. So an empire collapsing will cause the wait time for that turn to be longer.