I would say that it would be a pretty good idea for them to release updated hardware at the same time. I would suspect that they wouldn't go for a HDD, however fast flash would make sense as it doubles as larger and slower additional pool of ram as well and that unifies the Arcade concept with the Premium at a lower price.
Im not sure about making Natal mandatory, but I concede that its probably the only way to get developers to consider using and forcing them is the best method. Though best practices aren't always maintained, somewhere in the design documentation is a requirement that all games be 720P with 2xAA which means a lot of games don't fulfill the Xbox 360 requirements.
Tease.







