Goodreads is not a site for crowd-sourcing reviews or ratings. Goodreads is a site for cataloguing your book collection. And if you happen to add a rating or a review then it naturally feels as much "your" metadata as the date you read the book or the fact you've shelved it as a "holiday read" and "disappointing ending".
Having said that, Goodreads has such a large membership that mostly, especially for popular books, the idiosyncrasies of people's rating habits are averaged out such that a 4.3 star book will
probably be better than a 2.6 one. Usually.
I think picking a highly anticipated book from a massively popular series and looking at its ratings after it has only just come out is going to give you an outlier in this regard. You will end up with lots of 5 star ratings that mean "I've not read this yet but I'm really really excited about it."
Finally, as has been said before, if you're upset at the way Goodreads allows users to rate because you want a higher degree of certainty that you'll like a book before you read it - well such certainty is an illusion. Your favourite author can let you down, your most sympatico reviewer may mislead you, your trusted friend with the most similar taste can suddenly fall out of sync with you. You can minimise the risk but you can't eliminate the chance of not enjoying your next read.
Oh well, you'll just have to live with that.
