Episode 4 ended in the exact same manner though. Did their goal for the movie, with a bigger threat in the background.
Things weren't left as open ended with the characters in A New Hope as they were in The Force Awakens. Luke had the door open to learn about the force and he had an adequate use of the force to let him fire the proton torpedos at the Death Star. Things weren't in place yet for him to know about Yoda or the other things that the force allowed him to do.
Han Solo was mostly wrapped around. The rogue with a heart of gold who did the right thing in the end. The Jabba the Hutt stuff really didn't seem to be written as a problem that he couldn't have solved right after the events of Star Wars. He just stuck around despite having the cash to pay him back.
Princess Leia did what she set out to do which was get the Death Star plans to the rebels and destroy it.
Yes the bigger threat of the Empire was not resolved and Darth Vader got away, but the story on it's own (Before "Star Wars" became "A New Hope") we are shown a pivotal swing in the balance of power between the Rebels and the Empire.
Rey is someone who struggled with accepting her fate and does so at the end, but where her destiny takes her is all stuff they will address in the sequels.
Kylo Ren was perusing more power with the dark side o the force and will complete his training in the sequel.