Maybe not opinionated, but they should definitely be decisive. I've seen too many PMs just funnel every user request straight to implementation. No thought or care given to what the product should be or do. It ends up being a collection of poorly thought out functionality.
>I've seen too many PMs just funnel every user request straight to implementation
Exactly this! My biggest tool as a PM was the ability to confidently communicate with our users and tell them "thanks for that suggestion, it's a good idea, but no we won't build that, and here's why" in a collaborative and positive manner so that our users will continue to use our product but understand why we are building what we are building, and why we have a very specific goal in mind.
PMs should almost work backwards - they need to have a product's goal and desired outcome communicated effectively to everyone from the get-to, and then understand what needs to be done from there. They should know enough about the business needs and market needs to be able to voice their opinion early on about what needs to get built, how it needs to get built, and why it needs to get built...and then leave the rest up to the technical people, with somewhat consistent feedback from users, stakeholders, and the market.
Exactly. Opinions are what link the product vision to the users. They matter, and if you don't have them it shows up in the form of a bloated, unfocused, and often biggy system. Put another way, opinions are regularizers. Products without opinions and vision can be successful, but if you're only ever reactive to user requests, you'll never truly push into new capabilities.