Well, there is a grid (4x4), the items can't take any size and position.
Also, whether it looks "cluttered" is up to you. If you like, you can place icons only, like on the iPhone, to have it look that clean, or you can arrange icons and widgets in a pattern, or you can mix them... you're free to customize it any way you like.
I agree that the tiles could result in cleaner look, which is good, but not at the expense of functionality. Unfortunately, developers can't choose what size their applications should be on the home screen (the choice between an icon that's a quarter of a tile, a whole tile or a double-wide tile would make sense).
Again, I'm a fan of clean looks, symmetry and not too many colors, but that must not come at the expense of functionality.