This is a variant we have tested pretty exhaustively, and it works quite well, especially for those rare occasions where you get an extreme case of "card screwage" (like when you have 5 cards: Order Heavy, Order Mounted, Mounted Charge, Order Two Units Left, and Inspired Left Leadership, and all you have are MI and Auxilia, and no units/leaders anywhere on our left).
It's late in the game, and you are now card-screwed, and the enemy are advancing on your position. You play the Order Three Units Left card and do nothing, just to get it out of your hand, and you pull Order Two Units Left! What to do? If this doesn't bother you, sit on your hands (no pun intended) and play on. Or,.... you could,.... Mulligan:
"A player may discard his ENTIRE hand and draw a new hand consisting of two fewer cards than his Command. He may (or may not, we've played both ways and they both work!) immediately play a card from this new reduced hand. After this play, he receives two new cards, and the next turn two more, and so on, until his hand is back to full strength".
This is an interesting dilemma. We tend to prefer not to allow an order, as this simulates generals gathering under duress, and trying to hash out the Army's next moves. But it does silence the whiny babies like me, who just love to cry about their crappy hands!