I posted this: When you see The Voice and Idol both dropping to around 11-12 mil, you know that viewer fatigue is a big problem. Idol's Thursday finale got 14.3 mil. But Idol's main problem this season was casting, casting, casting. Nicki Minaj turned off millions of loyal viewers without bringing in the younger viewers they were expecting. And casting a bunch of lame guys for a viewership that's at least 62% female was a big mistake. I know they really, really wanted a female to win, but the cost was too high.
Let me add that the viewers who left the show were likely Kree voters, so it's very possible that Kree Harrison would have won if Nicki had not chased away her voters.