I'm not too sure about the finer points of Pelagian doctrine, but I'm pretty sure that he may have presented something worth considering. People are very good at raising the issue of original sin, and they have a history filled with hundreds of bloody wars, brutal killings and heartless cruelties to back them up. But what about the good stuff? Surely God pronounced his creation good before the fall. Surely we are not all totally depraved?
Chesterton writes that what is wrong with this world is that we do not ask what is right. And I think this is an invaluable insight into this issue: it's easy to negate the negative, but not so easy (or natural) to affirm the positive. I know enough moral atheists to be able to tell you that even the godless are capable of being godly. I know enough fallen people to know that even the fallen are reflective of the fact that they were created good. In the end, I have no problem with the doctrine of original sin. But I do have problem with the denial of the doctrine of original good.