So, first of all, what's a remake?
I won't define it from a dictionary but actually regarding the use of the word in the movie industry in the last few years. We can think of movies like Planet of the Apes, Psicosis, Clash of the Titans, etc. What they have in common is that none of the movies is just a re-make in the sense of just doing the exact same thing with better graphics (for example), but actually they usually change a bunch of stuff, keeping only the source material and the general feeling on that movie, being the story line, most events on it, etc.
So why would a completely new episode be a re-make of an old one? Well quite simple, everything happens pretty much in the same way it happened in episode IV. With the exception that this one has a slightly different context, this being the future, some characters are new, the girl is an orphan instead of living with her uncle and aunt, etc.
But let's get a bit deeper into this:
So in ep. 4 it all begins because of the message that was on R2-D2's memory which was supposed to be delivered to Obi Wan. And the hero is the one who run into the robot by change.
On ep. 7, it's exactly the same, with the robot being heard and rescued by the hero of the movie, just that this time the robot (BB8) has a map of Luke's whereabouts instead of a message to someone in particular.
So after a few events both in ep. 4 and 7, the hero(s) run into Han Solo and his ship, and the action starts, getting them to eventually work with the forces against the dark side.
And what was previously the dead star is now a much bigger one, a planet which uses the energy of a sun to destroy other planets. I have the suspicion that they've decided to use a sun in order to make it more credible considering the energy needed for some machine to destroy a planet. Nonetheless the idea is exactly the same, and how it is destroyed is extremely similar as well. Even considering the tiny battle ships flying trough little corridors surrounded by enemies and trying to penetrate the weapon.
Not to talk about the villain or his master, which resemblance is quite obvious.
So in the end basically what ep. 7 is, is just a remake in a different time and a little different context. Which uses a lot of the nostalgia that an old Star Wars fan might feel.
Indeed this movie will be loved and hardcore fans will never see this movie in this way, but that's all for the love for the franchise and the nostalgia, but for some other more objective fans this movie fells very short on what one could spect of a continuation on such a great saga.
Thanks for reading :)