If the devs are smart about this, introduce a mixture of new content with higher drop rates and cool-down, as well as more of the current type with low drop rates and frequent access.

The hard-cores will have lots to do with the non-cooldown stuff, and the moderate/casuals will enjoy higher drop rates with limited-access content.

Of course, the problem is (and will be) that too many players feel that they should be entitled to everything in the game, and should never be out of stuff to do, regardless of their play style or schedule.

Good luck making those types happy...