I personally don't like it. Windows 8, Windows RT, and Windows Phone 8 all have the same square, flat theme. And it works for all of them. It is recognizable. The concept that OP shows just blends in with the crowd and doesn't stand out. Plus it looks too much like Symbian.
Also, the square tiles also match perfectly with Nokia's square hardware. It just goes.
At first, I thought the ability to have wallpaper might be nice. Then I realized a) I'm not good enough at taking pictures to get one I want to see every time I look at my phone, b) it would be hidden behind the live tiles, anyway, c) I'd end up with at least one live tile that had a clashing color and looked horrible.
What's all the fuss about, they're tiles? By industry standards, "tiles" have 90 or 45 degree corners, thus the name for WP icons. I wouldn't mind a slight webOS-ish rounded edge, or at least the option to do so. Android and iOS have a noticeable gap between their icons while WP's tiles are butted up to each other. I don't see any resemblance but Apple might sue anyway if MS did it so it's a moot point.
I personally am against the the square flat look software has been going to lately. I design all my websites with border-radius on practically everything. Its amazing how something so simple makes it look so much better. I also put in several gradients. Its the difference between a website that looks primitive and something that looks truly amazing. I love windows phone, but I don't think that it needs to be square or mono-chromatic. In fact I wish it wasn't.