Honestly though, I'd love to see some way of rewarding players for doing "risky" behaviour such as flying in open, but the only way to really make that practical without running into stuff like blocklists, instancing and all the other million ways people could cheese """"""flying in open"""""" would be to just... reward actually instancing with opponents.
Not a strategic reward, necessarily, but a personal one. I'm not talking about giving a bonus to your next mission's slider-movement-points because you passed a hostile player in supercruise (though that wouldn't be too terrible, it'd be open to 5th-column nonsense of someone parking a "hostile" alt in a system while their buddies run missions)
Like, if you get into a fight with another player pledged to an opposing power, then win or lose you're still fighting for your power which makes your power think more highly of you. Even escaping from an attempted bushwhack could grant you kudos. For instance, successfully initiating a jump with a hostile player present could just give you a handful of rank points. Hell, being blown up could grant you a consolation prize. (no prizes for just logging out though - escape, kill, or die, those are your options)
This would in practice work out to be an open-only benefit since it's not a thing that can happen in solo. Sure I guess in private they could arrange to meet and interdict each other to boost their ranks, but honestly... if that's how they wanna spend their playtime then let 'em, same with any other technically-effective-but-incredibly-boring way of rank grinding. Maybe put a rate limit on how often you can benefit from being pulled by the same player? idk.