I agree. Ownership would allocate accountability for a "stupid" idea to the person who chose to create it so people would be much more likely to create a good idea for a Challenge. And ownership would also provide a person to review and validate completed logs - ie the "owner" who created the Challenge in the first place.
Totally agree with the idea of GC making a per state gpx file available. Also coming from Australia, it certainly would suit most people here I think. We all download the same PQs every week for our own state.