Man didn't even notice that with vaders light saber thing, nor did I notice the kid at the end had the force within as he apparently levitated the broom to himself which I missed.
So yeah looks like they're setting up for the future with anyone potentially having the force within (not just Jedi), and think this is how Rey is infused with it too. Why so strong is the question so hopefully there's more to it along the lines of what you're thinking and not just that any tom Dick or Harry can have the force by will (which if so might explain her connection to Kylo ren as like with Lea gravitating in space and Luke force projecting/shape shifting to another location, apparently these are powers of the force never revealed in any earlier movie).
Regardless of note, this was the first time I've seen a Star Wars movie where no one clapped at the end, and it's taking me a longer while to process everything, but, again, here's hoping JJ Abrams with IX wraps things up well.