In my experience, there are good workers and bad workers. Problem for you is that you won't know what is on your porch unless or until it is too late.
skid, I've spent much of my career working with people like you, who want nothing more than to help families fix problems. First time I did a termination of parental rights hearing with one of my favorite workers, she was in tears, and called herself a failure for a while. Many of the best like you do burn out, and the system is worse off for that.
As to the problems with CPS, it really is a no-win situation, and in many cases I have personally seen, it is made worse by children who use CPS as a threat against strict parents, and then even worse by some of the do-gooders who think that it is wrong to let your child participate in contact sports, or take children on vacation by car if the trip is more than six hours, or to allow children to participate in discriminatory para-military organizations (the Boy Scouts)...and yes I have heard all three of these arguments (and worse) in court.
