Things are a bit different here though, as they're talking about loading rather than streaming. For a start a Wuu game could be using 30 or 40 times the texture data of a GC game and several tens of times the geometry. And the optical drive probably isn't even 10 times as fast so decompression of assets could be far more processor intensive than it used to be. And the Wuu processor - if 3 overclocked Broadways - would only have about 15 times the raw power. So just going by these numbers (admittedly we don't actually know that much about the CPWuu) I could easily see a situation arising where you were in a more CPU limited situation for loadtime decompression and transcoding of assets than you were with the Gamecube.
Of course, this may have nothing to do with what the guy was talking about on Twitter.
On a slightly different note, I think the 360 can actually transcode on the CPU and then feed the GPU out of its L2 cache, for either textures or geometry. Maybe the Wuu could do this too, but unless it has the same vector processing throughput it wouldn't seem as well placed to handle it as the 360 (edit: without additional custom hardware I mean).
