"I can tell you Bill won't be involved. It's sad but we're passing it on to a new generation. Ghostbusters 3 can be a successful movie without Bill. My preference would be to have him involved but at this point he doesn't seem to be coming and we have to move on. It's time to make the third one" Aykroyd told the Metro according to HuffPo UK.
Well, perhaps this can be like the Star Trek reboot. Respected for including Nemoy, Shatner-less but great none-the-less.