How could he utilize that though?
It would be both great offense and defense.
He could shrink attacks making them less devastating, shrink his enemies making them less threatening and slashing the weight behind their attacks. Imagine him shrinking someone inside a big area of effect and then stepping on them, things along those lines.
It's not impossible. Law isn't the only who got an area of effect increase, Buggy got one too. The distance he can fly away from his feet increased from IP to Marineford. By the war he was flying almost as high as the frozen Tsunami.