1st Gen: PPU used for most things with the SPUs just doing some heavy lifting
2nd Gen: PPU still dominant but SPUs doing a lot more tasks.
3rd Gen: SPU completely dominant with PPU now more of a game coprocessor.

I expect the third generation of PS3 titles will really shine, the first engine that is really SPU centric and just treats the PPU as a coprocessor is going to kick arse. The SPUs are fast like greased lightning but just require a different paradigm thats not going to be fully incorporated for a few generationsÂ…"

As I said the rest of the article is somewhat technical, but if you can muddle through it gives an indication of the challenges that lie ahead for developers. His observations in particular seem to jive with what we've been hearing about PS3 development, and the fact that as the platform matures it will come into its own. Heavenly Sword has previously been rumored to be a launch title, but of course there's no mention of that on the blog.