You get that in Android, but do you need the same capability out of every OS? I don't think so. There's only so much you can allow in terms of customization before the underlying design philosophy is broken. Now, some people don't care about that, and that's ok. But some people DO care about consistency, flow, UI design, etc. Android's customization abilities are also its biggest downfall. You get the ugly, slow skins, you get folks adding widgets and wallpapers that slow the phone down and murder their battery life. I've had to help non-techie folks find important icons/folders/apps that get lost when they try to customize. All that randomness is the reason many Android phones with much better specs than Windows Phones run much worse, because there is just too much to account for.
There is upside to being able to customize to your heart's content, and that's an important part of Android for some folks, but don't expect Windows Phone 7 to be the same. And every time you ask for one more thing to change, alter, customize, etc. you are one step removed from a cohesive UI experience. I always get heat for saying this, but if that's what you want (the imo ugly ass pic you posted), get Android. Let the Windows Phone folks continue to focus on smoothness, cohesiveness, consistency, and user experience.