Aykroyd tends to believe his own bullshit entirely too much. He's said "we're moving forward on Ghostbusters 3
" about two dozen times over the last decade. (And if he thinks Year One
was a "serviceable comedy," the man is even further gone than previously thought.) At this point, it's been so long since he or
Ramis wrote anything good that there's no reason to trust any of their creative judgments anymore.
As for a new cast, anyone who didn't see that coming lives on a planet where crack grows on trees. That's been the approach ever since 1998. Sony wants a movie that can re-launch a franchise with a bunch of young, cheap stars, with 15 minutes of screen time for the old guard in order to lend the movie some credibility with fans of the original.
Keep in mind that no new Ghostbusters
film can move forward without the approvals of Sony / Columbia, Aykroyd, Ramis, Murray and Ivan Reitman. Hopefully, this movie will never get made.