I like Sammy's idea about one of the Ghostbusters getting hurt and yeah where is Winston in that though?
I honestly didn't think much about him. If you look back at the last two movies it heavily leans toward the big three that started Ghostbusters
Even in the courtroom scene in part 2. There's the moment when Venkman, Ray and Egon suit up. I know Winston wasn't charged with breaking the road but still.
It's always been about Aykroyd, Murray,Ramis.
It's the star trek phenomenon when two or three actors get the most focus