As I'm sure you know SS, defense seems to deactive with shortages, so it makes your war easier, and if offense de-activates...great.
I see exactly what you say but with PvP it's a bit different no? Presuming you have a half decent adversary it's not all over in one month, other things than just smashing the WI asap come into play. Just my way of looking at it.
I really didn't know nuking a target has no effect on the WI, that IS peculiar.