I agree with your thesis, but why should we trust your judgement? If you are only going to make 1% on the deal, what guarantees do we have that you won't accept a bribe? Finally, how can we ensure enforceability of your decision.
This isn't something that an individual can solve with a service, it's something we as a community need to solve and then subscribe to the solution. Look up the use of Dispute Resolution Organizations in voluntary societies as an example of a philosophical approach to this problem. The key isn't the organization but the community's respect for the DRO.
It's no different than mediation in offline life. Mediation is nonbinding. (Unless the parties agree to be bound by the decision of the mediator). Why trust my judgment? I have extensive experience in mediation. Plus I can guarantee my judgment will be better than screaming at each other in back and forth forum posts. All disputes will be decided based on principles of common law and equity.
And it is a service that is needed in offline life and online life for the same reasons. Besides, if both parties are willing to submit to the process, then both have clearly made their interest in amicably resolving the conflict known.
Why wouldn't I accept a bribe? Because I'm not a scumbag lol. (And that would pretty much guarantee I'd be labelled a scammer and never get any more business). Also once again it is nonbinding. A party would be wasting their money in bribing me to reach a crazy decision, when the otherside could still refuse to carry it out. (Of course unless they agreed to be bound by the decision originally)
Edit: But you did convince me of one thing. 1% for over 100BTC is too low. I've adjusted the fee to 2% per party for disputes of that amount or higher.