The worst thing about TFA is not that it is a rehash per se. The worst thing is that its sotryline is a complete shit.
In a good plot, elements naturally lead from one to another, are indispensable with respect to each other and (most importantly) all have a strong connection to the plot objective. On the other hand, TFA shitty “plot” is just a combination of random elements completely unrelated to the plot objective (i.e. search for Luke).
Nevertheless, the fact that they put so many unrelated rehash elements into the film played a major role in storyline becoming a disjointed unrelated pile of crap.