As a child of the '80s, I loved the Ghostbusters and still do. I've seen both features countless times and was a fateful viewer of the original animated series. I had the action figures (even the goofiest ones that were only seen in the toy line), the vehicles, the firehouse playset, the plastic tubs of green slime (still remember the smell), the costume with proton pack/trap, and I loved the sugary marshmallow cereal.
That said, Ernie Hudson as Winston Zeddemore has always 100% been a Ghostbuster team member to me. Even from a young age, I never understood why he wasn't featured on the original poster.
Yeah, I know he wasn't a "known" face to the public at the time and in the film he's the odd man out, but dammit he's just as much of a Ghostbuster as those three. Thankfully, he was featured on sequel's poster.
Now we fast forward to today with a little article over at MTV with Ramis chirping about GBIII. He promises the "core" members will be back, "including Bill Murray (Dr. Peter Venkman) and Dan Aykroyd (Dr. Raymond Stantz)." Now, it's probably just the way the article is written, but Hudson absolutely needs to reprise his role as Zeddemore as a Ghostbuster if this whole thing shakes out to become reality. The Ghostbusters are now like a longstanding band along the line of the Stones, if a member leaves or dies, it's essentially over and trying to bring a replacement in (or simply write him off in the screenplay) would just look ridiculous.
Interestingly, while looking for stuff on Hudson just now, I found this blog entry with pages from an old Starlog chronicling the quasi-struggle for the Zeddemore character to make it on-screen in the first place.