Yeah I am pretty sure many would accept a more serious tone. Extreme Ghostbusters had a much darker tone and had a bit less comedy in it. Definately much darker than it's predecessor.
This has been brought up a lot before and it is one of the things that makes Ghostbusters so special. Sure it is catagorized as a comedy, but it has some very good horror elements in it. I think that is something that made the film pretty unique in the time it came out. You go through the film and you believe the logic and rules that the movie sets up and as a result when something scary happens it gets a genuine reaction from the audience.
Now there is Absolutly no doubt that The Reboot is 100% a comedy. There is not a single moment in that film where you take the situation seriously. The movie is one punchline after another. So I am pretty sure that many would embrace a darker tone to Ghostbusters. I just wouldn't do away with the comedy all together that's what regular horror movies are for. What makes Ghostbusters work is the fine balance between comedy and horror.