There is no doubt that there are similarities, specifically done on purpose I would guess. However, I do not think that these similarities, done for nostalgia and as a nod to the original trilogy, take away from the originality of the story line.
Of course, if you want to look at the story in a vacuum and speak in generalities, then yes of course you can make it seem very similar to A New Hope. However, when you start to look at the differences you will see the originality behind it and in particular the different dynamic of the characters. That is the key difference; the characters are very very different in nature other than a comparison between Luke and Rey both being raised in a dessert environment and not knowing their past/force abilities.
However the similarities stop there. Rey is clearly a survivor. She has been on her own for a long time and does what she needs to in order to survive. She had no desire to leave Jakku (even if she always knew there was nothing really holding her there). Her command of the force seems to far exceed what Luke's was from the time they first became aware of their abilities - she is already using mind control. Contrast this with Luke who was always wanting to get off Tatooine and had a loving supporting family that was around. Luke was driven by a need to help others (following Leia's message) where as Rey, whilst having such virtuous qualities, was more of a reluctant hero.
Vadar and Kylo Ren have some similarities but their characters are mostly different. Vadar knew who he was and only questioned his position when faced with the death of his son. Ren on the other hand is deeply conflicted and ultimately took the path Vadar could not, he killed his father! Ren is deeply troubled by the light he feels inside and is clearly insecure and not in command of his powers to the extent Vadar was. Ren's background and upbringing are similar to Vadar (both were Jedi and seduced but isn't this generally how most Sith are arising at the time?).
There was no character like Finn in the original trilogy. Rey is like a mash up of Luke and Han. Even BB's personality was clearly different from that of R2. R2 always seems to know what he needs to do. BB seemed unsure of himself but always wanting to do the right thing.
The overall story line in a nutshell sounds like A New Hope, but once you flesh it out the similarities are nothing more than nods to the original. I'm not going to dissect the story line but I would still say the script is original.