I can see what you mean, but I think I'm an excellent parent, so I have a different view. I don't believe that would work for everyone, so would have an adverse effect with the way some children are brought up.
If someone 'trained' me to be a parent before I had kids, I'd have done things differently and by the book, so wouldn't have found my own way. I'm quite proud with my own results (so far). He wants to be a soldier at the moment, so I'm gonna have to try to correct that though.
It doesn't matter how much training you have, every child/parent is different, so it boils down to common sense and 'going with the flow' a lot of the time. There's no text book solutions to parenting unfortunately - all the good intentions etc when you're either pregnant or considering having a child go out of the window when the child arrives. Too much thinking and consultation on what to do in certain situations isn't healthy - you need to act fast with most things - it's either in you or it isn't due to experience.
I know some people need 'help' though - but I'm not so sure it's because they can't do it, I tend to think they can't be bothered to put the time and effort into it. A child develops their own personality etc by the time they're five, so those first years are extremely important, but they're also the years when parents don't bother so much because there's still in a state of shock at producing a child. If you do it 'wrong', you'll end up trying to correct problems for the rest of their child years - but you won't know which category you fall into until the child arrives.