How about a JUST God? God's perfection demands justice for disobedience. What you call vengeance, God calls justice. God gave Adam and Eve one command. "Don't eat of the tree that is in the midst of the garden, for in the day you eat of it, you shall surely die." What part of that don't you understand?
In your world, God tells Adam and Eve not to eat of the tree in the midst of the garden, and then after they do, God just says, "oh, that's OK...maybe it was a stupid command. I'll just pretend it didn't happen". What kind of god would do that? Not any kind of god that I would want to serve, because he couldn't be trusted. He could change his mind on a whim, and I couldn't believe any promise he made to me, because he could just decide not to fulfill it. Is that the kind of god you want?
God is Holy, and His Holiness cannot abide sin (disobedience or rebellion) in His presence. The Bible says His Holiness will kill you because no sinful flesh can stand in the presence of God. Face it. You are human. That means that Adam was your ancestor, and sin passed onto the whole human race because of Adam's sin. You were literally in Adam (as a potential human being) when he sinned. You want to know how serious sin is? It is so serious that God's imputation of sin to Adam and Eve caused a genetic change, which is passed down to this day. Sin is so serious that when Lucifer sinned and became Satan, He was kicked out of Heaven, along with 1/3 of the angels, those who rebelled with him. Sin is so serious to God that He flooded the whole earth, and only saved 8 people, because the rest of the world was so sinful that it actually caused God to regret that He had made man. Sin is so serious that the only way God could make it possible for man to have fellowship with Him, He had to become a man, in the person of His Son, Jesus, a new race of man, sinless, in order to pay the penalty for sin, in order to reconcile man to God, through faith in the Jesus, and repentance from sin. What you so casually dismiss as the acts of a capricious and petty God are acts of ultimate love and grace for you. He did it even though you don't deserve it. He did it because He loves you that much, that He would suffer death to make it possible for you to experience life with Him.
Now, do you want to reconsider your position?
This is the same God who humbled Himself to become a man and die a humiliating death on the cross to atone for our sins. You must counter-balance your criticism with this dogmatic teaching of the Church.
Evil and suffering is a great mystery, there is no doubt about that. But the ultimate "answer" is to be found at Calvary.