So, let's get hypothetical here. Imagine that First Class
was, indeed, a complete reboot of the X-franchise, set in modern times rather than 1962. Same basic story (Xavier and Magneto becoming friends, the Hellfire Club threatening global destruction to usher in the ascendancy of mutantkind, etc.). What would have to be changed to make it fit in 2011?
The most obvious, of course, is the story of Magneto. This is one of the great things about keeping First Class
a period piece, because tying his origin to the Nazis and Jews during World War II is absolutely perfect for his motivation. But since we need Erik to be a thirtysomething man in 2011, that obviously won't work. The closest modern-day analogy would probably be the ethnic cleansing carried out by the Serbs against the Bosnians in the early 1990s. They even used concentration camps. So perhaps Erik and his family could be Bosnians, and Sebastian Shaw could have been working with the Serbs. Fast forward to the present, and Erik is hunting down Serbian war criminals in an effort to find Shaw. It works, but it's not as good as the Nazi storyline, IMO.
The other big change would be the setting of the ultimate showdown. We obviously can't use the Cuban Missile Crisis, and since it's in modern times it's likely we'd have to make up some sort of situation into which Shaw manipulates the world powers.
Finally, the mutant lineup could be changed. By making FC a reboot, we could use the actual first class--meaning Cyclops, Jean Grey, Beast, Angel (the real one), and Iceman. It'd make sense to include Storm, too, so that Jean isn't the only girl. Mystique would still be included, of course. We'd need to include a sacrificial lamb to replace Darwin, though (unless we just stick with Darwin). Any ideas there?