TFA was a play-it-safe franchise reboot - and for all its "done better polish" it lacked a beginning, a middle, and end because its not written or intended to be a stand-alone film. Its a beginning leading to a middle. It is not a complete story. No one knew ESB and RoTJ would get made when ANH came out. As a result, ANH was written in such a way that you can watch it and say "I really liked that story." With TFA your left saying, "I really this part of a story whose overall quality can only be judged by what comes next." That's a flaw.
I don't know if it can be objectively said that that's a flaw. It worked alright for The Fellowship of the Ring.
It was a flaw for FotR too, it was just a good movie in spite of that flaw.
When a movie unlike A New Hope is made with the promises of a Trilogy, the idea that the first one is open ended is not a flaw but a tool to ensure that the audience returns to see what happens next.