So this is a new format idea, and it is just about how it sounds. A spellslinging variant of EDH where you use a sorcery as your Commander. Obviously there will need to be a couple adjustments and probably a separate ban list if it gets going.
I feel as though since there is diminishing returns for the multiple castings and the fact that you aren't getting a permanent, I would say only 1 addinional mana to the cost of the spell for each subsequent casting.
I think this could open up some interesting builds and I hope some of you take the time to make one. I will post mine as soon as I have it made.