I think what you're missing here is that the creeds are less a matter for individuals, than they are a matter for the Church, in the same way that the Constitution is a document meant for the government, rather than the citizens of the nation.
Also, the creeds are not a set of "fallible opinions," nor are they to be regarded as holy writ. Rather, they list those things that one must believe if one is a Christian. Take a look at the Nicene or Apostles' Creeds, and see if there's anything wrong with what they say -- and the answer is "no."
One cannot forget the context in which the creeds were written -- and I cannot help but notice that your individualistic approach to religion bears a striking resemblance to the environment that spawned those heresies -- and which the Creeds were written to combat. I'm not saying that you're a heretic; however, you're suggesting that people can use their own judgements on how best to follow Christ. As a member of the Episcopal Church, I have seen at first hand the damage that abandonment of the Creeds, and the adoption of "personal faith" does -- both to the Church, and to individual believers.
You're viewing the church as a human institution, in which case it is hopelessly divided and pitted against itself in thousands of factions. If the church is the ekklesia--all the individuals called out by God who are in Christ--it is not a human institution that can be organized and shaped into a hierarchy. I realize this will take some time to wrap your mind around this for anyone used to hierarchy, clergy, process, etc. But Christianity is not about those things--that is Churchianity, not Christianity. Being Christlike--now that is where the rubber meets the road. As for whether there is anything wrong with the Nicene or other creeds, that's beside the point. I dislike the use of creeds on principle, not their content. No, there is nothing that screams heresy in the Nicene, but my point is that one does not need to read and understand the Nicene (or the historical context it was written in) to be saved. God bless,
Gospel Union