Last week, right before Microsoft launched Windows 10 for phones preview, we revealed the two new tile sizes that Microsoft is experimenting with. As you can see in the image above, Microsoft is testing out a tall and large tile, offering app developers more space to showcase their app information. These new sizes are in addition to the small, medium, and wide sizes.
According to Microsoft's Gabriel Aul, these two new sizes are experimental and user feedback will determine if they remain in the operating system. "We're still experimenting with tile options. Even the double tall isn't for sure. You'll see more and can give feedback," he explains. Aul even mentions that more tiles may be on the way.
Having a tall tile on a smaller phone wouldn't be ideal, in my opinion, as it would take up too much space. However, if an app developer is able to utilize the tile and make it showcase information worth seeing, then I don't see an issue with it. But this will be incumbent upon app developers to make the new tile sizes useful.
It seems these tiles could be a pre-cursor to what Microsoft may eventually want to implement on Windows (both desktop and mobile) -- interactive Live Tiles. Remember the story from last year about an interactive tile UI system that enables users to access and manipulate Live Tiles in an interactive way with touch gestures? Basically, users would be able to provide quick input to the Interactive Tile on the Start screen. With a perception of Start as an entrance page, Interactive Tiles would be introduced to empower the start screen with an intermediate access level to applications.
We haven't heard anything new on this yet, but having various sized tiles would be a step towards that future. You can read more about interactive Live Tiles here.