According to the Synoptic Gospels, Judas Iscariot is the betrayer of Jesus. Because of his betrayal, Jesus is arrested easily or fast and tried and crucified eventually. But strictly speaking, Jesus's crucifixion would occur even without Judas' betrayal. In fact, Jesus became the target of arrest because he was dangerous in the eyes of Rome and Jerusalem. He was dangerous because his message and actions challenged the power system of the Roman Empire. He was against the system. He was supposed to be hated and killed by the power.
Therefore, we should not think that Judas helped Jesus die and that he cooperated with God by betraying him as if God planned to kill him. Judas's action was simply evil and is condemned. He cooperated not with God but with political-religious authorities. He did not understand God's will or Jesus's work.
Again, we must make it clear that God's plan is not Jesus's crucifixion. God wants Jesus to reveal the good news of God (not the good news of Rome) and his righteousness. Jesus did his best doing the work of God, risking his life. He was put to death because of his faithfulness to God and because of his recalcitrant spirit against the system. But God raised him from the dead.
Therefore, Judas Iscariot cannot be thanked for at all. Jesus's crucifixion or resurrection occurred not because of Judas's betrayal. His crucifixion resulted because he boldly proclaimed God's good news and his righteousness without sparing his life. His resurrection occurred because of God's power.
The high view of Judas comes from the later Gnostic Gospel--The Gospel of Judas Iscariot-- in which he is portrayed as a true disciple who understands God's plan for Jesus's sacrifice.
