Perhaps these two verses provide the strongest indication that the Lord/servant relationship is a literary device rather than an attempt to accurately depict the relationship between either the Father and the Son, or the Son and the prophets. The Lord sees the branches that do not produce good fruit and decides to destroy them. This procedure would be sound from a botanical viewpoint. However, the servant pleads to be allowed to save these branches.
Rather than indicating disagreement, this literary device allows for the continuation of the wild branches when the more logical action would have been their destruction. The allegory has roots in botany but reality in history, and the way the Lord works with his children is never so capricious as to completely destroy them when they first disappoint him.