In my experiance Defence does not seem very effective and hardly worth it, and from what i read other seem to find the same, the super high damage ships seem far more effective.
For this reason it would make sense to make a small ajustment to make defence a more viable option, something like making defence equipment slightly smaller so can fit a little more on would certainly add a little more balace, exactly how much of a change i not sure, that something i think should be discussed
If not a offcial patch tho, how about a Mod if anyone is willing
of course, the computer AI ships should be updated to compensate so as not to create unfair balance