Ok, I get why most of the bans are in place...
But,
1) Why ban nova? If you're worried about it being used to get a creature, just ban mutation instead (after all, without being allowed to play creatures at the same time, the uses for mutation are pretty slim)... Sure nova may spawn a singularity if overused but, without mutation allowed, only an imbecile would do so.
As a means of quanta generation, nova is not really that bad considering it could only be used on spells.
2) Why ban discord? Scramble is annoying, but without other means of support (creatures or spells) I don't think its that great of a threat. Without creatures or spells there will be no scramble/BH combo. Scrambling will slow the enemy down a bit, but I think thats only fair considering how difficult a creature rush would be to deal with using only permanents.
With maybe a few oddball exceptions this tourney is probably going to be dominated by pure creature decks. Spell decks will need something to help compete against creature based decks. Nova might just give spell decks a shot of winning. Likewise for discord and permanent decks.
That would make things more interesting I think.