I would like to hear someone ask, "What are you going to charge me with?"
They would answer in a heartbeat. "Interfering", or "Obstructing", or "Disobeying an Order", or "Disturbing the Peace". They have them all at the tips of their tongue, and have used them all against peaceful citizens documenting their conduct. They are in big trouble now that it has been found legal to videotape them, and that you have the ability to upload directly to the internet. They can't destroy the evidence any more, which they used to do routinely.
If Wilson did bring a guy in just for videotaping him, he is one of those kind of a-hole cops who likes to do what he wants without anyone documenting it. That doesn't have anything to do with what went down with good ol' Michael Brown.
They usually fall back on the good ol' "interfering with a police investigation". And if the actually do arrest them they can add "resisting arrest".
And that question was answered in the story: failure to comply with the order of a police officer. Now stop and think about that. Police can arrest you for failing to follow their orders regardless of whether you are committing a crime or not. There is something fundamentally wrong with that.
I know, I know! Ending a sentence with a preposition.