I could see very specific cases where arbitration makes sense with a very well defined scope. "Parties agree that disputes over widget quality related to this agreement are to be adjudicated by the Widget Quality Counsel". The courts are not always the best arbiters for every dispute.
However, what we have now is every corporation finding ways to slide arbitration clauses of global scope into every transaction. That is always bullshit.
Excerpts from the Wikipedia entry on libertarianism:
And
Don't feel too bad. Having no fucking idea what you are talking about just makes you a typical American style libertarian.
As for centralizing power, corporate personhood and broad deregulation are about the most radical systems for centralizing power that have ever existed. You are still ignoring the entire history of conflict between unions and corporations. Unions had their day using the "libertarian" model and all that came from it was disaster. It wasn't until the labor movement gained political power and had pro-union regulations put in place that unions had any real ability to negotiate with corporate power. But that's all reality so it's irrelevant I guess.