Trey Stokes was being far, far, far, far, far, far, far, far too harsh on this film.
Yes it was probably a cash grab but it was a damn funny one.
There's a good laugh and a couple of chuckles every couple of minutes. As a comedy it exceeds the required laugh quotant many times over. 99% of comedies being made today have nothing on this film.
Yes the plot using the same template as the original and I don't for one second believe they thought they were doing otherwise. They were deliberately playing off people's familiarity with scenes from the original and giving them a new spin.
The original Ghostbusters wasn't serious and this wasn't either. It isn't intended to deepen or evolve the universe of the Ghostbusters, it's meant to give us another two hours of fun with our favourite characters from the first film.
The reason why the Ghostbusters aren't Ghostbusters at the beginning of the film is because they were bankrupted by the state after being sued because of all the destruction they caused. Which if you see the political figures in these films is ENTIRELY PLAUSIBLE!
Also if there is one reason why this movie needs to exist it's "Do, re, Egon." Classic.