Intelligent doesn't imply dangerous. It doesn't imply _anything_ so long as it is underspecified. That is the core problem: what do we actually want, and how do we know it exists?
We want something that thinks enough like a human to understand and appreciate our goals, but enough different from a human to not suffer our faults. And in asking for this, we already suppose the existence of an AI that fundamentally disagrees with how humans make decisions.
This is the 'better morality' problem. If I say "I'm more moral than you", I have to do so by showing that _your_ morality is contradictory with _your _ actions; that you are a hypocrite. Otherwise, we will disagree on some course of action, and you will have no reason to believe your decisions are incorrect except by _assuming_ that I am more moral, which is what we are trying to establish.
So we really want a computer that can point out our errors and suggest corrections. This is one (vague) foundation for artificial intelligence that doesn't easily permit 'evil geniuses' since, so long as this is what the computer is doing, it cannot be said to be dangerous.
Overall, I find AI discussion to be incredibly primitive and naive. It's practically a religious debate except among a very very few. Most people are not very creative about addressing these kinds of issues, and it's depressing that people are tied up in so thoroughly in bad terminology and non-issues.