How did the commission plan make city government more effective?

I believe the answer is: powers were vested in elected commissioners who were experts in their fields rather than in a mayor and city council who usually were party loyalists.

By providing the experts with the governmental position, they could utilize their knowledge and experience in order to deliver the most suitable program to address the city's problem. Giving the position to loyalists would be inefficient since they are only consist of people pleasers that only care about how they need to get elected in the following terms.

because he had a big bear belly