There is so much for a product manager to do to tell a story, have influence, get alignment, create momentum, etc... And all of it simply comes down to know what you are after clearly. Those real decisions of direction, not of features or solutions or the HOW, are the real tough ones. They also predicate the product. As a product manager you need to make sure you know what those are. There's no shortcut. Unless those decisions are made and agreed upon, everything else will suffer.