the problem with the current model for building AI is training it based on existing policy and thought. Which means it'd just be what we have now but somehow hallucinate more contradictory policy.
There are other forms of machine learning that could be utilized. Some work more toward being given a set of circumstances to reach and then it just keeps trying to new things and as it gets closer, it just keeps building on those.
In a dictatorship with an AI being in control, I don't think there's a question of accepting consequences at they very least.
There is no such thing as best case scenario objectively, so it's always going to be a question of what goals the AI has, whether it's given them or arrives at them on its own.
That's where it would start. I imagine it would be capable to see the flaws in the system and rectify them. This most probably means we as humans won't come out on top however.
A sentient ai would probably be the most dangerous thing to the human species as a whole.
First of all, a lot of humans do see the flaws but are indeed unable to correct them. This would also show in the training data. The AI OP is talking about would be much more powerful to actually act and change something.
Don't confuse Artificial Narrow Intelligence (ANI) with Artificial General Intelligence (AGI) or even Artificial Superintelligence (ASI).
Your statement suggest you understand ANI, which is all the AI that we know today. However powerful they seem, they can only reproduce what they have learned from the training data.
AGI (or human level AI) will be more what OP means here. Sentient, in a way that it can make its own decisions, think on a human level, feel on a human level and act on those feelings. If it feels humans are not important or harmful to what it values, it will decide to remove humanity as a whole. Give it the power to govern the world and it most certainly will act not in our favour.
Until computers can be genuinely creative, and not emulate creativity, its not gonna happen. And when that happens, we're either getting the startrek luxury space communism, or a boot smashing our head into the kerb for eternity. No middle ground.