This scheme dont need reputation or trustness. If automate this in nxt-protocol then we dont need third-party as nasx.com for exchange.
Nice - I think we could indeed create an AT to do this. Because the code is open and unable to be changed after the AT creation tx is confirmed then it can actually be "trusted" to do things like this.
The tricky part is going to be able to make sure that people know a trustworthy AT from an "evil" AT (that requires being able to understand the code which is why that code needs to be as simple as possible).