I'm thinking they ran out of time when the intel chips starting shipping ahead of schedule, and this this update finally addresses the issues that could benefit from a new approach.
Besides, there are so many announcements down the pipeline that a new enclosure of the MBP is not that big of a deal. Leopard, iTV, Video iPod, Mobile OSX are more noteworthy.
The big announcement was the first Intel laptops.
How about a black enclosure, or one that is more durable and...