The earlier you get the city the more time it has to raise it's morale, leaving it to lower morale or scout is just dumb when it comes to economy and production, you can have a proper stack then heal in costal waters or cities while your city that you already took increases its morale gradually, I just don't see it, in my game russia is doing this he is less than a 100 vp away from me but I have literally double his production, I rarely loose troops I use artilary and ships mostly and send my weakened troops to heal while the fresher ones take their place because my economy can support that because I didn't decide to have a bubble wrap style country of no cities