I don't think CoP counts as mid-level content because of how difficult it was and the fact that the level cap went up by 10 every couple missions. If you did it while leveling up it was bound to be stupid difficult or maybe you didn't have a job leveled that was good for those fights, or you had to wait a while and level which caused some large breaks in the story.

Job quests are going to be mid to high level content. Shposhae is great and the low levels go by quick enough that you will get to companies and job quests in a reasonable amount of time. If anything I think a dungeon in the mid 30's would be fine to add, but as was stated, we need some long-lasting endgame stuff to have something to work towards and keep us occupied.