Oda doesn't know how to write Captain/vice captain dynamic.
This is again proved.
Either he end up clowing the captain aka Roger or doesn't portrayal the right hand of the captain well enough (Whiteberad as Xebecs right hand) going as far as even make it seem whitebeard was weaker than Harald.
If whitebeard wasn't already a well know character and his strenght made very clear by oda he would be looking like a complet weaking right now.
This type of writing is what make many underestimate vice captain of great pirate in this manga only for oda to show later that they are indeed very strong.