It won't take long until you can get hard disc and DVD enclosures that matches the finish and cross-section of this case and is designed to simply stack under the main case. It would be very cool to have a thunderbolt port in the bottom of the case for that, and with daisy chaining, and another port in the bottom of the add-on enclosure, you could just keep making your tower taller. But even if you're running cables at the back, it wouldn't be the end of the world.
But generally I agree that expandability has been compromised for design and as a result it looks like a great piece of kit for consumers, but maybe not so much for pros. I quite like the trashcan design though - if they'd build one with Core i7 internals, everyday RAM and standard GPUs I would definitely be very interested.