Clan Dimun Pirate Captain (4 str): Gain 2 strength whenever you discard a unit.
War Longship (5 str): Remove 2 strength from a random opposing non-Gold unit whenever a unit on your side is destroyed or you discard a unit.
There are a few things wrong with this picture when you compare both cards. For the sake of the discussion, let's assume Longship has the same strength and doesn't trigger on a unit being destroyed. Then it all comes down to whether gaining 2 strength it worth more than dealing 2 damage?
I just used the example above to ask the question of whether damaging is better than buffing? I think that there are more counters to buffing than there are to damaging. So for the sake of balancing you cannot exchanges their values 1 to 1.
What's your take on this?