Lot's of different sects had sprung up all over the place. Christianity wasn't a monolithic idea at the time and everyone had their own idea of what sacred texts were sacred. It was a nightmare of diplomacy as these would be a very contentious issues... not much different than it would be today actually.
So the Council of Nicaea must have been very interesting. Christianity was filled with Mysticism and strange interpretations that were and are hard to define. While creating the Bible was important, they were also trying to create the doctrine and make it as palatable to the majority of people as possible. Don't forget, this was to be the new state religion for everyone... not just a reorganization of christianity as a church but this was a new form of government as well.
So was it perfect? Nope. Was it an attempt to do good... Yup though it was also an attempt to redefine the right to rule. Don't forget. The Jesus Movement was proclaiming a new King... and the Emperor just agreed that Jesus and God were King... and guess who was chosen to rule over them all?