When it came to rebooting Ghostbusters, director Paul Feig made some smart decisions.

Despite the online hate, the new cast is genuinely a fresh take on the classic paranormal comedy, not just all-female but more diverse in all sorts of ways than the previous team.

Melissa McCarthy, Kristen Wiig, Leslie Jones and Kate McKinnon are all solid in the movie, with McKinnon's improvisations as quirky engineer Jillian Holtzmann providing much of the comic kick.

Chris Hemsworth is also smart casting as - in another role reversal - the dumb but pretty receptionist.

A feminist theme that sees the new ghostbusters overcoming putdowns by various male authority figures is handled subtly.

But the movie still feels like a missed opportunity:

It's just not clever enough

Star Wars: The Force Awakens showed how well it's possible to honour a movie franchise's past while cleverly introducing new elements.

The best recent remakes - 21 Jump Street, for example - are smart in the way they update their stories for a new audience while respecting those who remember the original.

Ghostbusters lacks that inventiveness.

The plot is largely a retread of the original movie - nothing wrong with that - but it feels strangely dated, derivative rather than a fresh re-interpretation.

And the way beloved elements from the original are introduced - the ghostbusters logo, the hearse they travel around in and the marshmallow man, for example - are handled without wit.

The climactic battle is unengaging

Like so many superhero movies featuring battles relying on CGI, the climax of Ghostbusters lacks emotion and any sense of danger.

It goes on. And on.

Lots of fireworks. Lots of repetition. Bloated and uninspired.  

The characters could have had more edge

When you see how edgy Aubrey Plaza was as a free-spirit trying to play nice in Mike and Dave Need Wedding Dates, you realise how raucous and energetic the recasting could have made the new Ghostbusters.

There was also the potential for some strong character development.

Kristen Wiig's Erin is a highly qualified, under-appreciated academic with a confidence problem at the start of the movie.

She could have grown into a powerful, confident and funny character over the course of the movie - having a triumphant moment and maybe even a legitimate romance with Hemsworth's Kevin - but that chance was missed.

The cameos by original cast members become self-indulgent

Appearances by past ghostbusters start out smartly with a briefly glimpsed bust of the late Harold Ramis.

But the movie throws away Bill Murray - literally as well as figuratively - and cameos by the likes of Dan Aykroyd and Sigourney Weaver become increasingly pedestrian by the end.

The movie throws away Michael Kenneth Williams

The great actor who played Omar on The Wire is cast as a federal agent who could easily be described in the script as Federal Agent #1 (black).

He and Matt Walsh, as Federal Agent #2 (white), get a few meagre lines then have to stand around frozen in a toy soldier stance. A waste of talent.

Hollywood had high hopes for Ghostbusters.

"This is a restart of one of our most important brands," said Sony marketing and distribution chief Josh Greenstein. "We relaunched a 30-year-old property by making it both new and nostalgic."

But the movie had just a lukewarm opening in North America on the weekend. It took $US46 million ($60.5 million), behind The Secret Life of Pets, which took $US50 million ($65.8 million) on its second weekend.

Variety reported Ghostbusters cost a hefty $US144 million ($189.6 million) plus at least $US100 million ($131.67 million) more in marketing costs, which means it needs to take at least $US300 million ($395 million) globally to break even and substantially more to justify a sequel.

Word of mouth needs to be strong to keep it running but that feels unlikely. Ghostbusters is a decent reboot but well short of a brilliant one.