In the western half of the Church, the priest has always been more closely associated with the bishop.  In the eastern half, the priest is more closely associated with the deacon.  Both are correct, it just has to do with emphasis.

In order to represent the bishop as a priest--and fulfill everything Vatican II says, the lay person must receive the Sacrament of Holy Orders.  A person cannot truly represent the bishop and be his extension without the Sacrament. A lay person cannot fully and perfectly be an extension of the bishop especially because a lay person cannot celebrate Mass or hear Confessions.