On my MacBook Pro, there is no numeric keypad, so player 2 can't really use 1 and 2. Any chance of supporting [ and ] or - and = for player 2 rotation instead?
First, that actually doesn't work because it seems to only operate on the numeric keypad 1 and 2. Second, if player 1 is using wasd and g and h, it'd be kind of hard for player 2 to reach over anyway...