'American Idol' singer gives Aerosmith song's lyrics a gospel flavor.By Gil Kaufman Danny Gokey performs "Dream On" on "American Idol" on Tuesday Photo: R. Mickshaw/ Getty Images/ Fox There's a very good reason the "American Idol" top four didn't mess around very much with the arrangements of the classic-rock songs they performed on Tuesday night: a) they probably weren't allowed to and, more important, b) these songs are really, really hard to sing as is. Take, for example, Milwaukee native Danny Gokey's choice of Aerosmith's "Dream On." The prototype for all hard-rock power ballads that followed, the song is from the Boston-bred band's 1973 self-titled debut album.