Isaiah is humble, righteous, principled, noble—a real prophet's prophet. His name means "Yah is Salvation"—"Yah" being another name for God—and his prophetic career lasts through the reigns of a whole bunch of kings (Uzziah, Jotham, Ahaz, and Hezekiah). When God asks him to speak to his people, Isaiah doesn't say, "I would be so good at that." He says "I have unclean lips!" Of course, he immediately gets a burning coal to the mouth, which solves this problem (though probably causing a few others, like charred lips), but it demonstrates the humility of Isaiah, nonetheless. He pulls a Moses, basically, imitating that prophet's humility before the burning bush.
Like other prophets, Isaiah frequently has to do extremely crazy things that God wants him to do. God forced Ezekiel to eat Ezekiel Bread, and he forces Isaiah to walk around naked for three years and to name his son "Maher-shalal-hash-baz" ("Hurry to the spoils!"). These wacky shenanigans add up to a kind of educational performance art—it's not just like Kanye West naming his daughter "North West" (unless 'Ye's trying to tell us something).
Isaiah is sending little coded messages to Judah. His own nudity is the defenseless vulnerability of Judah itself, and his child's overly aggressive-sounding name predicts how badly the Assyrians are going to mess up Judah and Israel. His life is a series of symbolic gestures and acts that demonstrate God's designs to people, even though they don't recognize them.
Isaiah (the character) doesn't just record prophecies and perform educational stunts, he also gives valued advice to kings and sets them on the right track. When King Hezekiah is faced with the Assyrian invasion, Isaiah helps comfort him, bringing him messages from God that tell him not to give in to the Assyrians and promise the destruction of their army. He also helps Hezekiah's dad, Ahaz, keep it together when facing another joint-attack from Israel and Ephraim.
Isaiah seems to demonstrate a little more sympathy of Israel and Judah's suffering than God himself does, though it may be true that Isaiah is demonstrating God's own sadness over the wrath that he's being forced to use on people. Yeah, it's this whole complicated multiple-identity thing. All the same, Isaiah does a lot of wailing and crying—even for the Moabites. Isaiah seems genuinely upset.
The Suffering Servant is at the very center of controversy in Isaiah. Some would argue that he's really more of a symbol than a character, but he's here in this section, anyway, since he's a pretty human-shaped symbol. To cut to the chase, the Suffering Servant is such an important character or symbol because almost all Christians think that he's Jesus. A surprising amount of common stories about Jesus' life are actually mentioned in the Suffering Servant account. Even a caravan of camels comes to bring him gold and frankincense.
It's not hard to see why. The Suffering Servant undergoes torments that are laid out in the Gospel version of Jesus' life. He's killed "by a perversion of justice" and is buried in a rich man's tomb. He's despised and reviled and rejected by the people around him. He atones for their sins, even though they fail to recognize him. He takes the place of the scapegoat, bearing his entire people's punishment on his head.
The argument against interpreting it this way is, of course, to say that the Gospel writers just copied down prophecies from Isaiah, layering them on to Jesus life. Jewish readers and interpreters usually see the suffering servant as being an image of the righteous people of Israel as a whole—possibly a version of the coming Messiah, as well. Just as there's evidence for the Christian position, there's evidence for this position too. In Isaiah 43:10, God says to Israel, "You are my witnesses […] and My Servant, whom I have chosen."
However you view the Suffering Servant theologically, he's an interesting figure for other reasons too. Whereas some heroes (probably most heroes in world literature) win their victories through strength and cunning, the Suffering Servant wins his victory through weakness and humility. This totally turns around the normal pattern and reverses what you'd come to expect. It's a revolutionary moment.