The two things that definitely would be unfair about it: there are US (and now Canada) trials, and none for the rest of the countries (to get the jitters out and make routine-adjustments based on the feedback from judges), and (this will be a lot more difficult to fix) worlds is in Orlando year after year - while US teams pay a lot less in travelling costs, the non-US team have huge bills year after year for flying to Orlando and they have to fight the jetlag that is worse with a multiple hour time difference (that is more than the 4 hours from west to east coast). That means based on the GPS coordinates of their practice facility the teams have different preconditions. If you fix those two things, I wouldn't have any problem to take the best teams to finals in the open divisions - no matter where they are from.