You have no idea if your idea matters until you share it.
Your work speaks for you.
Managers tell you where you are, leaders tell you where you're going.
Criticism is the best sign you're onto something.
I am a firm believer that you need a well-defined leadership role to deal with unexpected and non-linear side effects of people working together. You need someone to keep the threads untangled and forming a high-functioning web rather than a big snarl of a Gordian knot.
Good design isn't about making decisions for your users, it's about making those decisions irrelevant.