I think they're making Finn to be the purest embodiment of the light.
Yes, Finn doesn't have Rey's proficiency for the force like her ability to maneuver unfamiliar ships at high speeds, Jedi Mind trick people, and resist Kylo Ren's mental probing
But all of that power is peripheral to the core of the Light. Skywalker level power isn't what the force is about (or Star Wars for that matter).
The emphasis is on honesty, compassion, mercy, self-sacrifice, and other positive qualities.
If you've read the spoilers, 90% of Finn's scenes are of him showing these qualities.
Time and time again, Finn is seen being exceptionally brave with a huge heart; Resisting orders as a storm trooper, Helping Poe escape the empire, Cheering up other characters, facing Kylo Ren when death is certain, etc.
The writer is cramming it down our throats. Finn is the light.
He also has a couple lowkey interactions with Jedi/skywalker relics.
In one scene he's casually toying around with the lightsaber training remote luke used in episode 4. (he doesn't even know what it is)
There is also his mysterious attraction to Luke's light saber. Finn's mesmerized by its power and he treats it like the holy grail (instinctually).
JJ said that Finn is the star of the series, this is what it means
Luke might not be the key to the new Jedi order, Finn is.
Finn's the heart and soul of the Jedi in a way a Skywalker never could be.
He's unconditionally good.