I know going through quests is an often unpopular idea here, but I for one love them. Despite this though, there was one thing that I've never done due to the requirements: replaying my favorite quests.
For me it's mostly the Hildibrand series, some of the postmoogle quests, job quests, and a few other random quests that I'd love to relive, but don't have the time or dedication to level a brand new character just to do this. I'm sure I'm not the only one who'd love to experience Hildibrand's antics a second time, and more than just what we get through the cutscene viewer.
I would love to have the ability to play through any already completed quest from start to completion. Maybe change the journal at the inn, or create a housing item that alters the quest flags to allow you to retake the quest without any rewards? It doesn't even have to be instanced or anything. Just create a new flag or alter the existing flag to activate the original quest markers, and to not give you the original quest rewards, since the act of playing through the content itself is the reward this time.
How do others feel about something like this? I would certainly spend dozens of hours going through my favorite quests a second time, and it would in theory cost the devs very little time to implement.