It really does look great here. Now imagine (someone mock it up) the protruding camera placed on... the camera will 'break' those line breaks. And that (for me) this is how we can start to speculate to the use of liquid metal. I don't imagine anyone with a design sensibility really giving the go ahead to a camera being placed over horizontal lines in that fashion, it just wouldn't happen. So those lines are going to be as-near-as-dammit close as possible the feel and texture of the rest of the phone.
Didn't Ive say in an interview that he was being pushed to the limits in exploring the uses of new and interesting materials? He said that. He could have been talking about sapphire for the watch, but he could also have been describing the use of liquid metal on the iPhone.
Regardless, as it stands in the picture above, I like it. With the camera added, I wouldn't be so sure. But only for the reason stated above. It would sit over the breaks, and that would feel odd to me.
I think they may be going heavy with Liquidmetal starting this year. The Apple logo we have seen may be Liquidmetal at the very least. They may be using it for the body of the iWatch as well. It's a flexible material and can be formed in unique shapes.
My pure speculation is that the extreme top and bottom of the device where it curves could be Liquidmetal in the final production design, assuming they can color Liquidmetal and make it look identical to the aluminum. Granted this is probably unlikely, and instead it'll probably look like what we've seen and nothing will be special about it or the materials.
The extreme top and bottom of the device are separated from the rest of the device and attach to it, and the bands separate them. Liquidmetal can act as the antenna and it's ridiculously strong and scratch resistant, and the top and bottom which covers all four corners is exactly where you'd want the most strength for accidental drops. Plus those are the places where scuffs and scratches and chips are most common. Imagine if dropping the device on one of the corners which is the most damage you can get from an impact, did nothing. Couple that with the extremely durable, flexible, scratch-resistant glass we've seen, or sapphire, and you have by far the most damage resistant smartphone ever built (not counting luxury phones).
As you can see in this picture, the very top and bottom are shown in a different color, this is either to represent that they are separate parts, or that they are separate materials, or both.