I don't know why, back in the early days of FFXI, they didn't just allow the camera buttons to actually work while in-combat/locked on.
They work everywhere else anytime yo uare in 3rd person view.
Then, you pull your weapon out and BOOM. No more camera control. It's fixed where it thinks the camera "Should" be. The behavior really doesn't make any sense and it makes the game feel very rigid and it breaks any smooth movement flow.