No, I do not believe he had to die for our sins. The point is, he did die so that we might be free from sin. Read Jesus' words carefully. He wanted all to know sins ARE forgiven. Not once did he say, "Sins will be forgiven after I have been put to death."
Temple authorities maintained Jesus had no authority to announce repentance for the forgiveness of sins. They insisted there was no such covenant between God and man for Jesus to make any such pronouncement. Jesus insisted he had been given the authority, by God, for this message. Temple authorities said, Nope, no such Covenant/Testament exists. Covenants required a blood sacrifice.
Had everyone believed and supported Jesus about Repentance for the forgiveness of sins, no need for death. Note that Jesus said sometimes the seed has to die before it can go on to produce abundantly. He was willing to lay down his life over repentance for the forgiveness of sins. Ironically, because he did, the Temple authorities had their blood sacrifice that identifies a Covenant/Testament between God and man. Talk about a final sacrifice!
Jesus teaching that God's eternal kingdom is in reach of everyone right now has had a huge impact on my life, because God's kingdom is where we do God's will here on Earth as it is done in heaven. In God's kingdom we turn away from sin to obedience to the will of God. Obedience to God has preserved many of us from committing some sins; turning away from wrong-doing and replacing it with doing right also preserves us from committing sins. God's kingdom never has been something to go to after death. God's kingdom is where we will continue living after death.
To enter God's kingdom and meet him face-to-face in this life, one must follow the Way Jesus taught and walked. He is the Way, the Truth, the Life. No one comes into the Kingdom and face-to-face with God without following Jesus' Way, and his teachings. Following his way is what makes him our Lord; following his teachings about repentance of sins and obedience to God is what makes him our Savior.