...There are a lot of problems that we could use the extra intelligence for, but there are inherent dangers in creating something you don't fully understand.
And even then, knowing how to solve a problem, or having "extra intelligence" at our disposal doesn't mean anything unless there's political and moral will to implement the solutions. All you have to do is look at the actions of the European Central Bank in responding to the financial crisis, as an example.
You have economists who studied crises for decades saying that the ECB should cut interest rates and allow higher inflation, what do the brilliant technocrats in Brussels do? Raise interest rates leading to double-digit unemployment in large swaths of Europe.
In other words, when implementing the solution to hard-problems is politically or morally untenable, even the greatest intelligence isn't going to help you
And nothing of value would be lost...
Really?! What about culture, art, literature, music, which for an artificial intelligence lacking in emotion would mean nothing. You're so ready to throw-out the cultural history of humanity? When the cyborg army comes for you, I'll remember this.
...we will progress to artificial life and artificial intelligence in erratic steps - some large, some small - some hard, some easy....
But why would you assume that this is the case? Why is this kind of "progress"--a completely self-replicating artificial intelligence--inevitable? What evidence points to that?
Human beings don't even have a cure for cancer, billions of people lack clean water. Yet somehow (almost by magic or wishful thinking) we're supposed to assume that the human race will develop this technology in the next 100 years, and certainly in the next 500. What if it takes another 1,000 years?
Except by that point, the oil would have run out, and all the major cities are 30 feet under water. To believe that these technologies (AI, asteroid mining, fusion, nanotech) will see the light of day, you have to believe that we can undertake another Moon Landing when electricity is $10 kw/hr and the government doesn't have the money to repair a 50 year-old bridge.
You knew the job was dangerous when you took it, Fred. -- Superchicken