Granted, the over the shoulder and quick dash are similar to Gears of War, but that was derived from Resident Evil 4, so by proxy if you played Resident Evil 4, you've already played all three games?
Granted this is an opinion thread, I derive much more pleasure from the experience as a whole than based solely off one or two gameplay mechanics. GB:TVG will eventually get taken out of the 360/Wii and replaced with something else, as is the nature of the medium. However, it's like I've told everyone who asked me why I bought the Wii version when the 360 version is so much better looking, I can see times down the road where I will want to play one version over the other, and I could definately play either after watching the films back-to-back.
Often, as I believe Ben “Yahtzee” Croshaw once pointed out, we mistake nostalgia for quality. I submit that technically, it would be impossible for the C64 version of Ghostbusters to be a better game in terms of quality or in terms of delivering a closer Ghostbusting simulation. That said, you may prefer that version of the game, and that in and of itself, is absolutely fine.