The CPU does seem to be the odd man out from what developers have said. And while "PowerPC-750 based" (nostalgic side note, I think my iMac G3 was based on that) could mean something more like how the Core 2 Duo is technically Pentium 3 based, he did also say it doesn't have as many SIMD units as the Xenon either. Combine the low clock, low SIMD units, and small die size, I think no one expects this to be significantly more powerful than Xenon or Cell, even with a 6 year newer architecture. Even Intel couldn't go 3x smaller and 3x lower clocked on the same fabrication process from 2006 to now and have significantly higher performance.
Nintendo faithful like to bring up the GPGPU like it will fix all that, but not all problems can run well on a GPU, the bulk of game code will still remain on the CPU. The GPU could do physics and texture decompression etc, but an older mid range chip like that probably can't do too much else without taking a huge hit to 3D performance.
Does it matter? Maybe, maybe not. Maybe games won't require much more CPU power for a long time, and the modern-ish GPU will be its saving grace. Maybe 1GB RAM for games will be plenty for the bulk of its lifecycle. Only time and loose lipped developers can tell.