In game mini-games like Terra Master or Triple Triad
In regards to "content" I would love to see an in game card game that players can play one another, or they could challenge NPCs to play a game of cards.
I know everyone has their favorite card game from past Final Fantasy titles, so one of those, or something new, but I think it would be a fun distraction as well as open up more content that would be both PvP content (playing other players) or PvE (playing NPCs in towns or camps)
Cards could be collected, traded, found, dropped, bought, or won. Before a card game players could wager a card, or the winner gets to pick a card from the players deck. Or players could choose just to play and not bet a card, but perhaps an item, etc.
Later down the line, there could be tournaments held with prizes to be one.
Anyway, just a thought, would love to see this in game. Keep up the good work. :)