Did you not like the huge tiles and hubs on Windows Phone 7? Great news! Windows Phone 8 will now have resizable tiles and hubs, you can shrink them down to almost icon size and fit more tiles on your home page!
Update: You will have three size options, small tiny icons, usually size tiles/hubs, and double wide tiles if the developer makes it accessible. This really gives you more space on the home screen, it takes advantage of hopefully the larger screen real-estate that OEMs will make with 720P resolutions!
Update: You will also have options of more colors to the Start Screen!