Rock is used for a couple of reasons, it's dramatic and dynamic, but it's also timeless and will not date your product. A 2015 game trailer with a 44 year old song? Every era of music has it's classics but classic rock always works, where would Iron Man be without AC/DC and an album released in 1980? Personaly I'd have the fast bit from Mountain's Nantucket Sleighride or Black Sabbath's Symptom of the Universe in the trailer. Gary Numan's Films would also be awesome. Classics everywhere.