Unity has a bug were if you disable the preview line above the keyboard when entering text on Android, you will be unable to use the delete key.
Just to let you know, I had the very same problem some weeks ago before using your UI solution. After I tried 2D Toolokit UI it i can see the same problem occurs. So in that case you must set: TouchScreenKeyboard.hideInput = false;
Is there a way to disable the resizing of the Android Game View when the keyboard appears on screen?Android decreases the entire size of the game Scene so that it fits the area view above the keyboard. It would be great if the keyboard would simply overlay the scene. I haven't found a solution for this yet. On iOS this does not happend.