It got really obvious to me on what they was doing in series 7 when the top 4 was given much better song choices compared to everybody else in their year, and it's gotten worse over the years to the point of acts like Sam Callahan, Abi, Janet, and everyone that finished 3rd or below in last years show shouldn't have even bothered showing up as they was always getting misused by Simon because they "weren't his thing" which is code for "you don't shout at me like I'm some karaoke 80's wannabe."
This year I think the acts that will end up being misused are Seann, Kiera, Max, and Monica because again they don't fit 100% into Simon's little mold.