Quote Originally Posted by player1
On average attack is better, since sometimes, units can attack, but not be attacked, like at the begining of flanking, when attacked units doesn't face flankers. Or when two units attack one unit.
This is a very good point, although I suppose the reverse sometimes applies - you can get attacked and can't attack back. This may be particularly important regarding the armour component of defence, which helps against missiles. However, given that the AI is not so good at flanking or using missiles, I agree with you that attack is better.