I think that given the general trend at the moment is to increase the gameplay interface with Strat then nothing should be added to lessen the reward for hitting strat. As strat missions tend to be longer than town missions and given that towns already reward players with mucho bomber points (when hitting centers)then a ratio that further enhances local town strikes over longer range strat strikes is counter productive.
A Damage/Time score used like Kills/Time in fighter score would actually hurt the long mission buff pilots, as time is the constant factor and who has more kills over the same time has the better score. Average damage per sortee would equalize bomber score for all bomber pilots IMHO.
Its been asked for before. It was denied based upon favoring one style of play over another.