Well, Ironman still have a lot of disadvantages, especially when the game will be release. First, there will be probably a lot of bugs (like always), and I don't really want to have my game ruined because of this. Also, for the first games, we will have to understand the basic mechanisms. With country like USA, it won't be a problem, but with a harder country like Germany or France, we could lose the game on some stupid mistakes. There is also the mouthly save, which will slow down the game. And last thing, on this game we have only one war. So we won't be able to become stronger to crush the countries who defeated us like it was possible in EU4 or CK2. And lose during all the game can be a quite annoying, especially for choleric peoples like myself. So there isn't only good parts to Ironman.
But I think I will play with it for the achievements. And I will take the USA for my first game, so I can't really lose.