Nothing, per se.
Technically, it's fine. Strategically, it works in the Great Game against Microsoft.
But it's not something I want. It breaks the first law of the original design.
Quite simply it's an attention hog.
The older iPod, with its clickwheel design, required you to look at it only on occasion, when you wished to change the order of your songs, or find a new one.
The new one, with its insistent color screen, demands your full attention while the device is playing.
This is not a problem with Apple. It's in the nature of video. It requires full attention.
The problem is one the iPod shares with all these video phones, and the reason for the problem is, in a word, Hollywood. They want to sell video, video can fit into anything, thus they push to get video into devices like the iPod.
The move also makes sense on the basis of Moore's Law. Small color screens, with good resolution, are cheap enough to make this work at a consumer electronics price point. Storage is cheap enough (even 60
Gigabits Gigabytes of storage), and compression is good enough, so that a low-power chip isn't wasted in playback.
But what Steve Jobs has always understood, better than most, is just because something is good for the seller, and technically possible, doesn't mean you have to have it.
The best move, for either Apple or (when it comes out with its own device) Microsoft, is to open this up to developers, to podcasters and podvideographers, to see what they can come up with.
If everything is left to Hollywood, the new iPod will fail.