So basically you want to monetize the Activity Points Reward system? Activity Points already gives rewards for activity, and we have options that allow you to renew your streak in the donation shop if you break it.
However, we would never add a system that would make grinding for quest items easier. It would first of all be unfair to the many questers who have grinded for their gear for years and would hurt the community more just for a couple of extra bucks a month. You have ways to somewhat increase the odds of your drop in quest by changing the difficulty of the quest and the sacrifice system and that is more than enough.