if I understand correctly, it involves a single thread for the game, no PMs.
That's not the point here. The point here is we have an awesome idea but its execution is really-really difficult. Single thread or PMs or chat or email or whatever, the difficultly and the amount of calculations won't change, as well as the possibility to do mistakes. In the "Elements Eliminations" forum game that ended a while ago, plenty of participants (including myself) made countless mistakes by adding/subtracting false quantities of each element. If community doesn't has the patience to do a simple adding/subtracting right and to post it correctly in a forum game, what makes you believe people will take the effort to do all these calculations of RNG-less correctly?
However, this event is really possible and interesting between reliable, serious and experienced players. In other words, players who are willing to put time and effort in order to execute it successfully. As both an RNG-worshiper and RNG-hater I greatly approve of this idea. Well, I personally approve every Forum Expert idea of this round, so go go go PvP Events!