To be fair, Christianity did some pretty decent things during the Dark Ages. For instance, while many in Europe were abandoning writing, reading, learning, and books, monasteries preserved many of the lovely illuminated manuscripts we still have today and made sure at least a few monks could read and write.

I think it's impossible to truly know whether or not the world would have been a better place then without Christianity. It did give some people hope, and who's to say that Europe wouldn't have been just as bad off if it hadn't been ruled by Christianity? After all, the Muslims had not just a religion but a culture far different from that of European Christians, and that, perhaps more than their religion, is what allowed them to prosper. Also, baths. So, I'm really not sure.

As an aside, "Dark Ages" isn't the "politically correct" term for the Middle Ages. It's just not accurate. Some historians limit it to the Early Middle Ages, but most disapprove of the term altogether because it is misleading and suggests no advancements at all were made and it was just several centuries of ignorance and disease, which is not the case.