Episode 5 ended on a cliffhanger, yes, but only after we resolved the plot of that episode.
See, in the original trilogy it always felt like they didn't know they would be making another movie. Especially in episode 4 when they literally didn't know.
So they still all felt like contained stories. These movies are intended to be in three parts, which means its the three act structure in play, beginning, middle and end. We only saw the beginning part, and I didn't feel like it ended all that strongly. So now I have to wait until 2017 to see the ending. Then probably 2019 to finally get to the end.
It's almost like waiting to finish the Hobbit. Except even those movies came out with less time apart (a year is still too long to finish a story though).
This actually makes sense, as Poe did not have the force and Rey did.
But Rey's force was stronger?
She just started using the force that morning.