Last evening, I taught my night-school class on a biblical theology of servanthoood. The students raised again the question as to whether Isaiah's servant figure might be the so-called anonymous prophetic author of Isaiah 40-55.
I answered that I doubt it. Israelite prophets channeled word of God's judgment or salvation to Israel, they did not embody and enact God's salvation as the Servant does. In Isaiah 49:6, God tells the servant that he, the Servant himself, will both restore the remnant of Israel and become a light to the nations.
Israelite prophets did not claim the right to demand a hearing based on their own special personhood as the Servant does in Isaiah 49:1.
Unlike any prophet, the Servant claims to be Israel (49:3), and to be God's covenant in himself (49:8).