I'm probably in the minority here, but I was hoping for some more distinct design changes to the MacBook Pro.
In no way am I implying that the previous generation design was poor, in fact, I love it; neither am I saying that retina and the thinness of the new generation is not much of a design change, it's a great achievement. (Hope that made any sense lol).
To me, at first glance it looks like the now previous gen MBPs until you see the screen and how slim it is.
Sounds like you're wanting change for change's sake then. Personally, I think the current design is close to perfect, so a thinner version gets no complaints from me.
The only thing I dislike about the current version (and all Apple's current displays) is the highly reflective screen, due to the untreated glass they put in front of the display. But this time they mentioned a significant reduction in glare, so that is something to be happy about too! The website says:
This Retina display doesnt sit behind a layer of glass, it is the glass. Which means you get all the benefits of a state-of-the-art display vibrant colors, high contrast, and wide viewing angles with very little glare. So theres more to see, and even less to distract you from your work.
Finally Apple!