TAM accident report
One of the tenets of Human Factors or Safety Engineering is that the best way to prevent accidents is to make the hazard inpossible to cause an accident and the least effective way is to rely on training.
I can't think of a single reason why anybody would want one engine in climb thrust (or a significant amount of forward thrust) and one in reverse. I've asked around and no-one I've spoken to can either. Therefore, make it impossible to place (or keep) one in reverse if the other is in forward thrust above idle.
Cheers,
Dick