I take your points dazzat however some points need to be addressed.
Berrigan is not a better defender. Smith, Farah etc make 40 tackles per game in the middle of the ruck.
Berrigan defends @ centre is is very good at it. If he had the responsibility of making 40 odd tackles per game in the middle of the ruck, he would not go as well in attack.
For Berrigan to be your hooker you need a centre who can play hooker in defence.
Berrigan is also now where near the kicker Cameron is, can do it, but please not anywhere near the vision or skill of Cam.
FTR
Smith.