Instead of trying to segregate hardcores vs. casuals, why don't we just give more incentive for hardcores to play with casuals. Add something like a new type of tome that you get for having a player in your party who has never completed that specific duty? Have those tomes used to make the best gear in the game better. Sure, you could run through a bunch of stuff with your current FC,LS, etc. but eventually you would have to reach out to new people, so there would be a certain point where the hardcores are looking for noobs to help. If something like this was implemented it would make the most hardcore player also the most helpful to everyone else.