I think the captaincy should be debated.
I recall Harris had a few games where he didn't start last year. If he struggles again this year he might start from the bench again. If he doesn't play 13 and plays in the front row instead he could end up part of the rotation.
Barnett and JFH would be the ideal starting pair.
As a captain his experience helps as he's probably our best at talking with the referees. It is likely his last year and if he struggles he may not be on the field for long minutes.
A co-captain or a new captain should be debated. Next year we will likely need a new captain.