If by "centralized 'mechanism'" you mean the fact that tonych control all 12 witnesses I'd say I don't think the mechanism of changing witnesses is somehow deactivate 'till the distribution is over.
I think it's in full blow validity and someone who present a very compelling argument to be one of the twelve witnesses could assume the role.
Now, tonych may have any number of reasons to be in this role, but one would be: the network had to start securely somewhere, and the other being: no one's showed up yet with the needed reputation and credibility.
Finally some voice of reason. I felt so lonely with my arguments among all "hodl, to the moon etc." mindless cheerleaders. Thanks for that. It would be nice to hear from tonych what is his plan (if any) for relinquishing control over witnesses and breaking down the current one man cartel. It's obvious that it's very early to talk about that but some plan needs to be outlined if the system is to be considered in the future something more than privately controlled currency by one man. It's so centralized at the moment that the wallet "decentralized value" slogan sounds like a joke.