Others have touched upon it but separating by age won't actually solve much if anything. I know there's at least one DCI corps that has it's adult members and staff take BSA youth protection training (required for that corps' insurance if I recall. BSA considers adult to mean 21+ so age outs must take it and volunteers and staff must take it annually). The BSA program isn't perfect (the alum/volly for said corps likes SafeSport) but having something in that spirit, with consistent implementation of policies and consistent consequences for when something goes wrong, will have much better impact than acting like setting divisions by age would be even remotely equivalent to the differences between Open and World classes.

I am a huge proponent of regional tours, but what I think should happen is there needs to be more regional options, ie bringing back regional circuits and having corps (new or existing) participate in them. That would require that DCI and DCA be supportive of these circuits existing and that they be supportive of corps that operate mostly or completely regionally- including corps that don't travel to finals. As is, DCA requires corps go to finals, DCI barely cares about SoundSport and the treat all-age class like shit. National tours are significantly more expensive and it's what killed a lot of the corps from back when there were hundreds of them, but it is what a lot of the kids want nowadays. As long as it's feasible to have both, I think we should have both and we should promote both as valid and awesome experiences.