If you ask someone who just worked on a great project to rate the project manager, very rarely will you hear them say the following:
"Great! He really knows his MS/Project!"
"Wow! She's a wiz with Earned Value!"
"Top notch. You should see how he links all the dependencies together."
"Stupendous! She can do a backward pass with her eyes closed!"
More than likely, you'll here something like:
"He was extremely visible and gave us the confidence that someone was running the show."
"She was able to remove all of our barriers and communicated extremely well throughout the project."
"He was really on top of the issues, yet didn't micromanage"
"She offered clear guidance and goals, and fully engaged the team, soliciting our input wherever possible."
See a pattern? While it's important to master the "mechanics" of project management, ultimately it's all about leadership --- the soft skills. Unfortunately, when organizations send their project managers to training, they tend to focus on tools training, or training in project management fundamentals. Certainly these are valuable, but the real need (and most frequently ignored area) is training in the soft skills.
And the best way to train people in soft skills is some kind of course that offers simulation training. It's good to understand theory around conflict management and psychology, but there's nothing like simulation training to really sink in.
So, if you want to really make a difference in how your project managers are perceived, focus on leadership training, including team leadership, presentation skills, communication, conflict management, negotiation, assertiveness, motivation, and other soft-skill topics that can define people's perception of the project manager.