So, from what I know, the rules for Defense still hasn't been re-evaluated by the developers (like mentioned in the FAQ thread). I'm sure I'm not alone in thinking that the rules for Defense, as they stand now (only the best source of Defense counts) just doesn't make much sense.
So I've been thinking about an alternative way of handling Defense in my campaign. This is very much a house rule, that will have an effect on how combat plays out, but let me know what you think. Have I missed some important balancing element in the rules if make this change?
So, the house rule is simple. Instead of having Defense as Setback dice, each point of Defense works by increasing the Crit rating for the attack (just like Massive for vehicles). This works for vehicles too, and stacks with Massive, meaning that huge capital ships will be even more difficult to inflict Crits on (which makes sense in my opinion). Also, when using this house rule, Defensive and Deflective qualities stacks with static Defense like that from armor and cover.
Using this house rule will keep the die pools smaller, and gives Defense a specific protective function, much like Soak.
-E.