We will mostly have to agree to disagree.

But one last time:

and particularly the one stakeholder with ~1/3 of extant stake, because 30x over representation grants them inordinate power to influence the witnesses.

Except that it is isn't 'inordinate'. In a perfectly fair system, a vastly larger stake should have vastly larger influence. In simple election terms, 51% wins and 49% loses (though in this case it is more like 60% and 40%). We just don't really like that outcome at the moment, so we try to come up with voting rules that gives 49% a chance at some sort of partial win, blunting the influence of the vastly larger stake. This obviously also gives any minority attackers a chance at a partial win, making the chain less secure in general.