I think Earth War did it in the least imaginative, and farcical way it could be done. I rather liked the power-loader-type-thing from the later matrix films. We've seen these types of exo-skeletons / mecs in literally all of Blomkamp's big films, so I would fully expect that he would be prone to doing it again. It's all about the story though. If it feels forced to have it there, it doesn't matter how good the design is. It won't work..