The problem with saying this is that Jesus’ actual teachings do not allow for it. It is true that the Gospels do not record Jesus saying, “I am God” in those words. However, he did say, “Anyone who has seen me has seen the Father” (John 14:9) and another time he said, “I and the Father are one” (John 10:30). This statement would be understood by all as a claim to divinity. And we know the crowd understood it this way, because they picked up stones to kill him for blasphemy. Jesus made many of these kinds of statements, which are too numerous to list here. In addition, he continually claimed for himself authority, status and power that belong to God alone. No Jew would have said the things Jesus said unintentionally. If these statements are false, they are either blasphemy or the ravings of a madman.
To say that Jesus was “just a good teacher and nothing more” is not an option. If you do not believe that Jesus is God, then his teachings and claims are false. Great Christian writer and scholar, C.S. Lewis put it this way: “A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic – on the level with the man who says he is a poached egg – or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God: or else a madman or something worse.”
If the things Jesus claimed about himself are not true, then he cannot be a good teacher. Someone who lies and intentionally deceives others cannot be considered good. Or if Jesus’ believed those things and they are untrue then, he was a lunatic. And an insane person with no grounding in reality could not be considered a good teacher either.
So you see, you can call Jesus a con-artist or a fool. Or you can throw yourself at his feet and worship him. Those are the only options. What you cannot do is say that he was a nothing more than a great human teacher. Jesus is either God or nothing.
Scripture taken from the New International Version.