AD14 was choosen for no real reason. It is the death of Avgvstvs, but it doesn't really matter. I don't believe anyone has ever gotten to the end date. If you play that long, there will be no other factions left and the entire map will be yours.

I think the 66BC crash is still in there. I heard recently that it is impossible to get rid of. Though it only appears for the factions that are Roman (for EB that is Arche Seleukeia, Hayasdan, and Baktria). Again, I don't think anyone has ever gotten there.