In the company I fly for the captain is always the PF on ground. I agree with that.
Some Cop`s have enough experience to do that but the less experienced ones are sometimes out of the loop till line up.
What about the argument that cops are able to fly but not taxi??
At first not always they are able to fly. The second is that in my opinion it`s easier navigate around the airport with all the navigation data inserted on the FMGS than on the ground when Dead Reckon NAV is required.
Cheers