It was changed because players were shrinking the clipboard down and using it to block the sun.
Having the sun blazing away is a game feature. How many time dids you read a story, watch a movie and they talk about how "the enemy dove out of the sun".
Ahh yeah I remember that one:
The enemy dove out of the sun, the sun glare hid him masterfully from his enemies, his red icon was barely visible, showing he was rook and closing in at an alarming rate at 1k yards.