Well, you can put some borders between buttons. I'm not suggesting on fully reconfigurable keyboard, while that would be interesting, I don't think that it's strictly needed. Physical keyboard layouts are static and that's OK. But the ability to display different labels on buttons might be handly. For example every Russian uses two layouts: English and Russian layout. Russian keyboards have both letters printed, usually with different colour. Now displaying correct letter on each key when user switches layouts, would be an improvement over current situation.