In The Zone most definitely had filler...
I completely agree with a reviewer who was reviewing Femme Fatale. He was doing a look back on some of her work, and he said something along the lines of "It was Britney who elevated the music on ITZ, not all the actual music itself. Everything surrounding the album raised the bar, the music videos, and the performances..but not the music itself". He went on to compare it to LOUD and The Fame, which he also said benefited from the very same thing...which was Rihanna and GaGa elevating the album, not the music.
Showdown, The Hook Up, Brave New Girl

, Early Mornin, Boom Boom, and Outrageous were borderline filler...they could barely hold up to the albums highest points..which were the singles. If any other artist release those tracks, I wouldn't even give it a second play.
I love ITZ, but more for everything that surrounded it. The involvement, the epic performances, and the videos. But it's my least favorite album from her overall. I even listen to Oops more than ITZ
