Your idea seems novel on paper but you forgot to account for "Burn out" as well. The system is designed to create breaks to prevent burnout that comes with progression and grinding. Only a small percentage of progression players would actually the take time to do anything outside of their groups if your system was in place because if they can clear the turns clean they would just farm them get what they need and still be too busy or burnt to help others who may wipe and impede them from doing other content.

Your concept is built around the idea that Raiders have that time. Concerning your PF issue, I personally raid 4-5 days a week and the last thing I would want to do is join a PF that may waste my free time when I could just get the loot with my team and be done with it. For me there is no incentive to help people on a turn I have no problems clearing when I could be doing something less stressful or something else that piques my interest (crafting, gathering, relic, being social).