Ghostbusters 3 is such a ****ed up mess. If Murray isn't in it, it won't be as good as it could have been. If Murray agrees to do it, but half-asses it, it won't be as good as it could have been. Honestly, and I say this as a huge Ghostbusters fan, but it's starting to feel like the most preferable option for me personally is a reboot. Ghostbusters is awesome. It's a fantastic property and it doesn't deserve to languish in the sad state it's been in for all these years.
Maybe it's just me, but I've always looked at Ghostbusters and thought, "What could have been...". They made such a cool world in those two movies, and they had such great style. I always felt it could have been a much bigger franchise than it ended up being. Maybe a reboot would allow the franchise to realize that potential.