I cannot accept that John did the choosing regarding which representative miracles to record. Since I believe this gospel contains the words of God Himself, I believe He did the choosing and the record is for the purpose of producing believers in Jesus the Christ, King of Kings and Lord of Lords.
Jesus saw fit to give us some examples that displayed the glory of God, that is, the miracles were for the purpose of giving glory to God, with any healings, etc., as secondary benefits.
He was giving us a foretaste of what conditions will be like in the Kingdom of God.
Well, you're right there and John would also agree. After all, John recorded several chapters on the subject. :O)