The fourth-generation iPod shuffle, released in September 2010, restores the button controls missing from the third-generation model. It's effectively a return to the industrial design of the second-generation model, but smaller and svelter.
However, the decrease in size comes at a cost. The second-generation shuffle was sufficiently large in one dimension that its rectangular shape acted as a visual and tactile cue to the user as to which way around the shuffle and its controls and clip were. Now, the new shuffle is almost square, and there is no longer an obvious cue.
With its clip to attach to clothing, the shuffle is reborn as functional jewellery - rather like a watch, if worn rather more like a brooch. But who chooses to wear square jewellery? Square jewellery with cheap white plastic inserts, at that?
So, here's a simple speculative redesign for a future fifth-generation shuffle, where the all-metal case is curved to echo the 'forwards' direction of fast-forward and play. Even if you're holding the shuffle and looking at the back, the orientation and where to press each control become obvious.
Other thoughts: This would be the first shuffle to sit the right way up in its dock. Apple will never produce a shuffle in this particular shade of cyan. But shrinking the internal electronics to fit, and even creating an internally-sealed headphone socket that doesn't let water in further, set into an otherwise hermetically-sealed case to give a water-resistant shuffle, can't be that hard; after all, Apple has considered redesigning the internals of the headphone socket. If someone wants a photorealistic 3D rendering of this idea... well, I look forward to seeing how your work turns out.