Andygjustis
I mean, can you imagine Ryan Reynolds and Jack Black's freakout/interaction when they get into it for the first time?
Priceless.
I wouldn't be interested in seeing that at all. It's already been done - in the first movie we see the guy's reaction to first seeing a ghost and trying to catch one. Let's face it, their first bust ever without even any equipment tests, went pretty sucessfully. I think it's safe to say not much training is really needed to be a Ghostbuster - Ray hired Winston without even knowing anything about him. A film about training a new team would be completely pointless.
I can think of one way it could work, however. The new cast could be part of a RIVAL Ghostbuster team. One that's putting the originals out of business. It'd be different and not been done before in a Ghostbusters movie - in all businesses you will always eventually get competition.
At the end maybe they have to settle their differences and team up to stop the greater threat, where they could merge companies (and call it Ghostbusters of course). I'd also like to see the original cast die at the end (as long as the new team doesn't trap them) - would be funny to see the Ghostbusters end up as the very things they try to catch.
i dont think thats too bad of an idea. they could have jokes of the real Ghostbusters tryin to like make bargains, sales, etc. to try and keep up with the rival Ghostbuster team. (free balloons and coffee mugs! )