I don't think there's a need for weight since there are many reviewers. The weight is the percentage of people who thumbed it up.

How does weight have anything to do with amount of reviewers? Those are completely unrelated metrics.

The current suggested rating is influenced by your history of rating, with weight given to how highly you rated it. There are shows that are suggested at 4 stars for my wife but at 2 stars for me.

This. And based on my history of rating, Netflix had been pretty good at guessing if something will be 3+ stars. If they think it is 3 stars, I consider watching. If they think it is 4+, I tend to really enjoy the suggestion. Though, nearly every Netflix original is suggested at 5 stars, lol.

I agree. I even want a couple more increments between 2,3, and 4. There are a lot of movies I see that I think are better or worse than a 3 rating but don't justify a 2 or a 4. I feel there's a lot of room for nuance around the middle area.