If you're looking entirely for the gameplay (or if you also enjoy Japanese themes, art, and humor), try the Disgaea games. Vastly better gameplay than FF: Tactics, though the art and tone are almost polar opposites.
Loved Disgaea but I feel like the endgame is too repetitive and boring. Like, in one of the games, if you wanna go to the penguin world you're looking at like 150+ hours of grinding. It's not World of Warcraft you know?
So I guess I'm looking for depth, but not depth for the sake of depth, more like real continuous flow. I liked Disgaea a lot though back in the day.