From 0 to 10 (0 as worst) How do you think my resolution:

1)Differentiate offense and defence in war support: “Surprise war” debuff should only apply to aggressor (nations propose demands or declare war), defending side shouldn't have any automatic war support lost, it should remain the same until attacker arrive. Traitor (level 2,the Silver one) might encourage other state to from coalition.

2)Sent notice when an ally is in war, nation could rally or swing their ally to join the war instead of demanding them to do so.  Or total war style.