Wasn't Jesus just a good moral teacher?

It sounds respectful, but it's the one option Jesus didn't leave open. A good moral teacher doesn't claim to forgive sins, accept worship, and share God's own name - unless those claims are true.

C.S. Lewis put it bluntly: a man who said the sorts of things Jesus said would either be a liar, a lunatic, or exactly who he claimed to be. He could be the Lord, or a deceiver, or self-deluded - but not merely a wise human teacher, because wise human teachers don't make themselves the center of their own message. The one option Lewis left off is the modern one: that Jesus never said these things, and the claims were legends added later. But the divine self-claims sit in our earliest and best-attested sources, not only the latest, so putting the words in his mouth after the fact does not fit the evidence either. You're free to reject his claim, but "great moral teacher" isn't a way to dodge it.