But then again, if we want the SAME game, we might as well play the original Halo: CE. I think there should be stuff that add to the game without taking away it's mysticism. Basic orders, like the ones I mentioned above could be implemented with the Cross by assigning each order to a button: up, left, right, or making one button to assign all the orders by rotation (one tap = defend, two taps = advance, three taps = follow player). I think this option should always be available to the 1st player when in co-op.
And when the player doesn't give out an order, then the marines, units, just go like in the first game, minding their part.