On a giant challenge league:
As Gorm pointed out I think challenge leagues don't let you admin games (either if one needs to be defaulted, or if one needs to be reset and un-defaulted).
Also, currently the division winner gets a small purse (like 40k?) for winning the division, that would go away in a challenge league (this is mostly helpful for new teams rising through the divisions).
It should make admin easier, so it's in their hands, but I think it will just change the headaches, not eliminate them.
Finally - I like ntw's suggestion for this season.