That's already the case for Zynga's games on iOS -- they have a very different feel when played on mobile devices, and have even found different audiences. "Words for Friends doesn't do as well on Facebook as it does on the iPhone," for instance, "because they are a mobile first experience. Our poker game does well on the mobile as well."
This doesn't mean that Pincus is saying Zynga's working on Xbox ports of its titles. Instead, the company is building out the tech right now to extend these games out in various forms to even more platforms in the future.