General comment (unrelated to Mathman): This thread already has had so many questionable (IMO) ideas that I will feel free to add one of my own -- carrying the notions of others to their logical conclusion.
If new rules were in place such that Nathan were to go to Worlds as GPF champion (and not as a representative of the U.S. chosen by USFS for a slot earned by the U.S.), then he should have no access to any USFS/USOC resources/support during the time btwn GPF and the conclusion of Worlds.
No funding of any kind. No travel expenses or logistical support. No access to the OTC or any of its personnel (such as his ubiquitous trainer). Etc., etc.
For all intents and purposes, he would not be a member of Team USA when at Worlds. Not announced/introduced as representing Team USA. Not allowed to wear the Team USA jacket. If he were to win, the U.S. flag would not be raised. The U.S. national anthem would not be played.
These rules would apply to any GPF champions (whether Evgenia or Kaetlyn or Yuzuru, etc.) and their respective federations.
I am dubious that such rules would be good for the sport.
(I am not trying to pick on Nathan, whom I like.)
I think such rule would actually make federations and skaters not support such rule.
While just forcing some selection is bearable for feds, and good for skaters (more chances to qualify if anything), removing national funding is not doable (for example, take a look at how Alina lives. Are you sure a skater like her can afford traveling to worlds on her own, specially on her first senior year?), and feds will not want their best skaters not to be part of their country team.