IMO they should add a 1 hr wait timer, so if you're doing a run with your ls, when finishing the dungeon you can go kill some NM's before you can enter again, dungeon content will last a little longer and you'll be doing something different in every run.

Not all Linkshells have the time to be 24hrs on, in my case we have like a 3-4 hours events 2 times per week its fairly enough to get 1.19 before we can finish 1.18 content