I think with all the advances RED offers over previously available cameras we sometimes take certain features for granted. The EPIC doesn't provide just a slight full rez framerate increase over Scarlet, it offers 70FPS more! That is more then double. That means the hardware has to handle more then twice the data per second. At 2K the EPIC does more then SIX times the framerate. That sounds like a serious hardware upgrade to me.
EPIC has to be many times faster. It's like the difference between laptop(Scarlet), 4 core tower (RED One) and a 16 core tower (EPIC).