On my PLD/WHM I will only do the LLR for the daily tome and will stop when I'm capped. IMO the 7500 gil tank role bonus is worthless when there are so many other things to do at 50. Maybe turning that 7500gil role bonus into 100 Allied Marks will actually draw tanks and healers into the LLR. I know I would seriously consider it.

I think there are many mis-matches between intent and reward in FFXIV, LLR role bonus is one of it. Allowing premades isn't going to help. You're just gonna have even less tanks and healers because they'll all just earn their daily bonus with buddies and call it a day.