Uhh... I imagine it's different with each situation and product.

But look-- if you're letting other people come in and define your vision for you... well, you're no longer doing management-- you're following someone else's vision and they're managing.

You own the product vision. You choose what to incorporate.

I'd ask google so you can find some books and in depth knowledge. A comment or two in a forum is decent for tips, but if you want knowledge, I'd go seek it where it is developed in depth: books.