As a manager it's an interesting balancing act. There are reasons things are done the way they are done and sometimes they are "because we've always done it that way" but more often it's because we've done it enough to understand something someone new to the company or industry doesn't. It's hard to know where to let go and where to draw the line.
I try to provide an environment where new people can 1. Try an idea and watch them fall on their face because they didn't understand best practices. 2. Then try to encourage understanding of those best practices and how they can be improved and change slowly to minimize impact or unexpected consequences.
I applaud your willingness to let people try new things, but the way you describe it seems to assume that all new ideas are bound to fail. They aren't. Different is not necessarily better, but better is necessarily different.
My point is that most new ideas do fail. People coming in don't realize that and it creates quite a bit of resentment. But people learn from mistakes and giving them the opportunity to fail is a good thing.
After that they can take the time to learn why best practices are best practices. From that understanding we can talk new ideas.
I've had so many employees come in convinced their idea was the best idea and then be frustrated and resentful that we wouldn't immediately start using it reciting the mantra that we do it "because it was always done that way".
I try to provide an environment where new people can 1. Try an idea and watch them fall on their face because they didn't understand best practices. 2. Then try to encourage understanding of those best practices and how they can be improved and change slowly to minimize impact or unexpected consequences.