Posted sometime last year in the features thread. Not sure if this is the correct place to advertise this or not.
Instead of having a flat rate of 60% attack success and 70% defense success, a morale boost card could add +A% to your chance of attack kills and/or +B% to you chance of defense kills for C number of turns.
Maybe this card could also have a positive effect on your luck as well?
Related Suggestions by les:
Rampage - Offense +20%, Defense -20%
Vigilance - Defense +50%, Offense -100%