In fact, the opposite is true. With the large number of people applying to become police officers, many recruits who are hired have more than the minimum requirements, even in small agencies. Also, more and more, larger departments are requiring officers to have college degrees to get promoted. A captain might need a master's degree. I support mandating higher education for police officers because I believe it is a major step in improving the level of police professionalism.
Discretion means that police officers can choose to strictly enforce the law.
If this power, however, is used to ignore or not enforce more serious crimes, it can be abused. The best example is speeding. Every road has a certain speed limit posted, and any vehicle traveling even 1 mph over the speed limit is legally breaking the law. However, I wouldn't want to live in a community where everyone who was doing 36 mph in a 35 mph zone was stopped and ticketed. Common sense says that police officers should target the more serious violators, even though going 1 mile an hour over the speed limit is still breaking the law.