It is amusing that a historian that comes from the future, tells us that he has a sense of humour and enjoy 21st century comedy such as The Simpsons. Is that your objective, to humour us?
What if the one-world government has problems? I don't think there is an absolute ruler, is there? Or is it a group of presidential people that work together?
One thing you don't excel in is religion, and particulary the judeo-christian god. He is good, he allows evil as we reap what we sow. The sin implanted into our very physical being makes us like that. Our sin is the cause of disease, pain, suffering, sadness and eventually death. This is just a religious view of a Christian like me, but others wouldn't agree. I'm currently studying on the world's holocaust and the end, so your story is hard to believe.
So what happens to the Darwinian theory exactly? Scientists really believe in evolution and natural selection? Darwin is what he makes man out to be, mere animals. Animals in flesh, and of course a conscience that deters our so-called 'evolution'. I wouldn't emphasize on this as it is out of topic.
So if you are immunise against 'everything', why would you still fall sick? In fact how do you even contract cancer for that matter? Cancer cells live in each and everyone of us, it is just mere growth or mutation that gives us that disease that is cancer. How do you immunise that?
So what becomes of spam, really. Do they still pop up in your 'internet' age, informing you how to date beautiful singles and stuff, or do those animated britneys ask u for cybersex. Its such an annoying problem, happening to me right now even with countless protection, that your age can tackle this problem.
It's such a cold, cold world out there in 2522. Some where I will never ever want to be.