If attack and defense points for modern war follow the same formula like CC then you won't notice the attack and defense points making much of a difference in the early levels. But at higher levels (100+) the multiplier effect that attack and defense points applies when attacking rivals will start making a pretty big difference.
Once your attack and defense stats start getting into the 20,000+ range you'll start to notice that you'll be able to consistently beat an opponent with 5000 more defense than your attack if you've invested heavily in attack points and your opponent hasn't invested much into defense.
This is only if funzio is using the same formula for MW as CC though.