You can have a previous clear check button if they also add a you can't quit button.
specifically for learning parties as I'm sick of running in those only for some elitist ass wipe who thinks it's a clear farm group to rage quit after 2-3 wipes.

back on topic
A previous clear button would be nice if only to remove the "show your loot/proof" mentality, I've cleared mog ex quite a few times, even farmed it but have had no luck with loot.