If we are playing with Weap expensive, we might run into the same problem we found in SAS6, where some aspect of the min. damage bug made some ships and starbases cause inordinate amounts of damage, though I would have to check up on the correspondence from back then to see exactly what it was that happened. On the other hand, if this game is only Weap expensive and not also slow tech advances, then that might not become an issue.

But to be original here we could do Con expensive, could also be fun

So explicitly allowing the damage dodge, not immunity.