Prophesy was a large part of the revelation of God and the content of scripture, but most people seem to have missed the calling and purpose of the prophets. It was never strictly revelation, but the application of the word to real life situations in a call to repentance. The signs and wonders were always given to convince or motivate wicked men to consider the message. The fact that some of their writings have become part of the Canon is coincidental to their purpose, but obviously according to God's will. The Revelation of God in the person of His Son is complete and the Bible is sufficient to teach us all we need to know about Him, but scripture alone is insufficient to convince of truth and convict of sin (or everyone who's ever read them would've instantly believed and been born again). That's the work of the Holy Spirit.
It's relatively easy to point out someone's sin based upon scripture alone when that sin is done out in the open, but how is hidden sin addressed in the church? Have you ever been in a congregation where the pastor took a break from verse by verse treatment of a book, and gave a special message because God moved him to do so? That's the gift of prophecy at work, even if the pastor doesn't realize it. God has given him a specific message to address a specific issue affecting his congregation, even though he's unaware of the issue. If he already knew that there was a problem, he could just approach the people involved and address them outright about it. When the pastor himself has a problem, you would hope that the elders of the church would recognize it and speak to him about it. Unfortunately, when Christians "go astray" we tend to rationalize our behavior and hide it, leading to more and more sin, until we confess it or are found out. The principal job of the prophets has always been to approach leaders, rulers, elders, congregations, etc. to warn them when they've strayed from God's purposes. How has that changed in the church age? Consider God's anointed King David. His anointing enabled him to write a large part of scripture by the Spirit of prophecy, yet when he sinned with Bathsheba it took Nathan the prophet to open his eyes to his own sin.
I realize that my argument may be self serving in a sense, but I need to defend my calling to a church that has negated the scripture by the consensus of leaders who would usurp Christ's authority and deny the relevance of what scripture itself says.