Yes, he could be a ghost. But, his acting wasn't the heart of those films, it was his writing. Harold Ramis will always be known as Egon to many. But, he'll be known as one of the greatest comedic writers of our time to a great many others. If there's a movie from the late 70's or 80's that someone deemed a comedy classic; it is most likely that Harold Ramis either wrote it, directed it, or both. His credits include Animal House, Meatballs, Stripes, Caddyshack, Ghostbusters, Ghostbusters II, Groundhog Day, Analyze This, and The Ice Harvest.
Harold's absurdest and intelligent approach to comedy made him one of the greatest comedic minds, ever. His work went onto inspire a generation of comedy directors. Especially, Paul Fieg, Adam McKay, and Judd Apatow. As a pioneer of R-rated comedies, I like to think he snickered a little about dying at age 69. Thank you for the laughter mister Ramis.