The idea is great and honestly, I would like to find a way how it could work, but for now, these are my key points:
reviews/feedbacks are great, but they're useful only if people who buy the product, service, or something else read it (that's why it's usually on the vendor's website)
the separate platform would make things a lot harder for the user trying to find a product and suitable feedback on the feedback platform. It would require a very specific and unique categorization of products, services, or experiences in order to prevent duplicates and a total mess
manufacturers could still give fake feedbacks and no honest opinion would be guaranteed
it wouldn't raise the already low percentage of the feedback given for each product (people just don't have a habit of giving it)
the idea of making it possible for anything is great but it already exists (Tusk, Increment.me). Why is it not so known? Tusk because the topic disappears after three days (very private and targeted feedback) and Increment.me because you also choose the people who you want feedback.
So do we need publicly available feedback site, exclusively for feedbacks/reviews? Well, I am not sure.
Still, things are some things that could make a change and thus, make this platform important:
superior method of feedbacking (easy to give detailed feedback)
credibility (the opinions are real and trustworthy)
high level of categorization (easy to find, no duplicates)
high accuracy of matching the feedback with the real product/service (links)
At the end, I realized the best way would be to collect all feedback information from the internet, categorize it and make it a big database from the beginning. That way there would be no harsh start. What do you think?