16 directions would be difficult for a couple reasons. Currently I'm using the function characterPatternY to transform the direction, and there's only 8 rows in a sprite sheet. Also, directions in rpg maker are stored internally as numpad numbers, and only supports 8 directions by default.
16 directions is definitely doable, but I'm not planning on adding it myself. If you want to try implementing it yourself I would reccomend editing Sprite_Character.prototype.characterBlockX and switching to the next column of sprites when the camera yaw is certain values.