Vision is good, but any product decision is still a guess about what will further your goals. Guesses can be right or wrong -- or if they are never wrong, then you're not doing anything that every other competitor in that space won't already be doing too. (And in that case, why have product management at all? Fire them and hire more engineers so you can follow the taillights faster.)
There's a difference from a blind guess and an educated guess.
And honestly yes, you shouldn't have product management. Projects should be coordinated by product leads and their engineers. The only people that can plan a vision for software are the people who make it. You're paying these engineers for their knowledge, use it in all capacities.
