The environment got the "priority" because there's a bigger volume of things to rehaul texture-wise, and also because yes, you are looking at the environment more than your character. Rarely will you be as zoomed in when in-game as you are in the character creator. An updated, "4k" character in an non-updated world is more jarring than the opposite, especially in XIV's case where the environment lagged behind the general quality of the character models.