Thank you very much for sharing your opinion. I really understand your point. Zidane and Vivi have more combat oriented arcs, although, I argue that the main story is still guided by Dagger's arc. Zidane has almost no development during the game (which is not bad, but he doesn't grow or change much), and Vivi has an amazing development that deservers its own analysis, but that halts during most of the game (after we meet the Black Wizards Village, there's not much new about Vivi).

Of course, this is a matter of opinion anyway. In another lens, I think for a teaching-perspective, Dagger has a better arc to expose the Three-Act structure :)