You can find clear numbers via lucky bancho's census, can search for that and it will lead you to reddit posts about it, since its a JP blog. They are snapshots of clears at specific times, based on how many people have the minion on lodestone. You can generally tell by participation who finds it fun. As for optional, ugh...the hall of the novice is optional, and that teaches you the basics of your job. I doubt people here want it optional, they want it mandatory.