It was the perfect blend of Hollywood and documentary.
As a history student who has studied this battle for years, I was thoroughly impressed by the level of historical accuracy, down to small details that even I was surprised to see, especially in a Hollywood film. It does a great job of depicting the events that lead up to the battle, like the Doolittle Raid and the Battle of Coral Sea, and also effectively and accurately portrayed the tactics and decision making of the commanders during the Battle of Midway. Yes, there were some Hollywood effects liberties taken, but it did not get in the way of portraying the heroic actions of real servicemen on both sides of the battle.
If you judge this movie with Hollywood standards, it might not do so well. However, Emmerich was going for historical accuracy and honoring the soldiers of the battle, which he undoubtedly accomplished.