dark ages are the consequence of the fall of the Roman empire. It created a political vaccuum filled by local lords. So not going through the Dark Ages (which by the way saw the developpement of many interesting thinkers, especially political thinkers, economic thinkers, and others, so it's not as dark as it seems) would imply we live in a sort of Roman world or that the empire would have collapsed later and we would maybe still be in this era of political vaccuum and unstability, I believe.