Totally agree police departments need better candidates but that intelligence thing is not true at all. The one case that started that rumor was just a police department doing age discrimination against a candidate, and covering their asses in the lawsuit by using intelligence because it's not a protected class. It was never about intelligence - it was age discrimination.
What police departments need is better training, a smaller mandate (i.e., mental health professionals need to be called to those types of events), and a big enough cultural change that normal people at least consider doing the job, like firefighters.