But, the prequels and the classic eu already introduced the idea of more force sensitive people and beings in the galaxy?

And initially, I thought Rey was a Skywalker given her resemblance to Padme and Shmi, until actually watching the Disney sequels completely debunked that. I would have settled for her being a Kenobi. Clearly this is LF’s fault in the post Disney buyout for not having a concrete storyline in the first place.