This album needs to be viewed in the context of Outkast's six previous albums, rather than just with reference to Speakerboxxx/The Love Below. Hit singles such as Ms Jackson and Hey Ya thrust Outkast into the mainstream, but before this they had released 3 top quality albums. Southernplayalistic.., ATLiens and Aquemini appear to fall more easily into the rap genre, but were just as progressive both lyrically and musically, albeit in a less obvious way.
Idlewild represents an amalgamation of the various ideas that Outkast have experimented with over the past 12 years or so - they really have been around that long. We have Big Boi's synthetic beats and 'Rooster' rapping style from Speakerboxxx, and Andre's jazz piano and singing was a recurrent theme on The Love Below. Going back further, rapping styles characteristic of Stankonia - think Gasoline Dreams in particular - are revived on 'The Mighty O', and the jumpy blues theme as tried in Aquemini can be heard throughout. With so much going on it can be hard to notice the tangy guitar licks so prevalent on ATLiens underneath everything, but they are there in the more soulful songs.
Idlewild's new twist, the musical theme, is arguably far less groundbreaking than some of the artistic leaps Outkast have taken in the past.
With Idlewild, they are now singing from the same hymn sheet with a result that is pleasing to listen to, if slightly too vaudeville for some. As a consolation, the sound is funked-up to a degree extreme by even Outkast's standards, and the collaborations work well.
The real question is, where do they go from here? Idlewild feels like a consolidation based around the temporary theme of the musical, and hence it may be something of a stop-gap. It looks like Antwon is going to be another rapper turned actor. I have a suspicion that Andre would love to produce a rock album. He could be the next Jimi Hendrix.. or maybe just the next Bing Crosby if the affair with swing turns into something more permanent.