Jut putting together random thoughts:

In Dragons Dogma there was kind of a worldwide solo raid boss. You could enter the instance once a day and fight it until it would retreat, and the damage of all players who fought him that week would then be accumulated to see if it had been defeated. If so, there was loot for everyone who contributed, and next week it would be back with more HP, so it became harder to kill with each iteration. If you died while fighting it, your damage didn't count and your try for the day was done.

Granted after 150 iterations it got stale and the thing became pretty much unkillable, but it was a fun activity, pretty much unlike anything I had experienced prior. I'd like something like that, a little fun daily "solo raid" where it actually makes a difference if you die or not, that has players working on something together while still allowing them to do it when it suits their schedule.