The Driscoll deal looks like a lack of accountability and/or failure of governance to rein in a man who believed his own press. (He declared himself the Mars Hill "brand?" Really?) Doesn't really matter his theology at that point. The inflection point (it looks like) was 2007, when Driscoll pulled a coup de main by expelling those who would hold him accountable, replacing them with yes-men, and changing the church by-laws to vest him with greater authority.
I have attended charismatic speaking-in-tongues, flopping in the aisles, holy-roller, near pandemonium services with objectively better governance and accountability than what can be seen at Mars Hill. The elders in the church had real authority to keep a pastor from going off the rails or aggrandizing power to himself or abusing his authority. The church was also part of an association that also kept a gimlet eye on things. I am not the least bit charismatic, but it was kind of impressive to see some of the inner workings. Most those big church scandals seem to be from independent churches, not The First Baptist Megachurch of Sometown (Southern Baptist Convention).
No accountability within the church, no accountability from without. Driscoll doesn't have to be a demon or an ogre, just a man. How many could resist the perks and little corruptions if one's abilities had brought such success? Those little corruptions lead to larger abuses of trust and then of authority--all justifiable by the wildfire success of the church, books, etc. Look at the Jaques Barzun quote in my sig. "The world has long observed that small acts of immorality, if repeated, will destroy character."
Anyways, that is how I see it. We are all fallible and almost all of us have an earthly price. Without accountability from within and from above, it seems just a matter of time until Screwtape and Wormwood twist mad success into a trap.