I didn't mind putting a superpowered villain, but i would have prefered them to be more original. Before the original WoK movie, Khan wasn't really very well known, the Director simply took a story from the original episodes and expanded on it since the character was still alive, i think they would have achieved more if instead of trying to do what worked in a previous film, gave another element from the Original series the "Khan Treatment", Gary Mitchell for example had a lot of potencial.
Though the idea of only focusing on Admiral Marcus's corruption also sounds interesting.