Jim, your question and your reasoning both have caused me to think, but I must include that I do hope your reference to Acts 2 isn't the evidences of the charismatic influence having an effect.
We have the completed Canon in our King James Bible. If that stirs controversy, that is not my motive, but I shall not be moved.
A question arises, "Just who can know the Mind of God, His ways are unsearchable and past finding out?". To know the prompting of the Spirit is to really be in touch with Him.
I say this not in boast, but in replying to your question, I have been "moved" by the Spirit to preach a certain message and even knew where and when I would preach it. I had a 2 year stint on a local radio station every Sunday, always live and never recorded. I gained tremendous experience to be prepared to preach. I must admit at times I wasn't really sure the Lord prompted me to preach what He helped me to prepare, but when I began to read the scripture and started to preach, the Spirit took full control, He "hammered it" into my soul at that very instant. I cannot recall a time He changed the message in the broadcast room, but I did feel led during the prior week to change directions by His promptings.
I almost always preached to the lost, but at times the Lord confirmed in my heart there were those listening who needed more to help them in their walk with God. For instance, one morning , while on the way to the station, the Lord prompted me to preach "When I get saved, where should I be?" Hebrews 10:25,26. He helped me that morning in an undescribable fashion.
To think the Spirit came upon the men as in Acts 2 and wondering if He still does, then we would no doubt spend endless hours discussing scripture in references to the subject.
No, I don't believe the Spirit of God gives the "gift" of tongues today, excuse me, I am not trying to detract from the subject at hand.
I rarely preach the same exact message twice, I am not like most evangelists with a "pouch" full of "smooth stones" , if you understand what I mean. I have only been led to preach the same message a couple of times, always the Gospel Message, but not exactly the same "points and subpoints".
Looking forward to other's imput.
Brother Ricky