@Darklight99 Usually influential films are defined by their ability to stand out and the lasting effect they have on the movie industry as a whole. The reason Akira Kurosawa or Orson Welles are brought up in all film school classes is because the way they tell their story, both visually and through story, changed the movie industry as a whole.
Akira was, at the time of its creation, the most expensive anime film of all time and the first anime film to have a major theatrical release outside of Japan. It revolutionized animation by using already recorded dialogue to animate the mouth movements of the characters and was a major turning point for adult-themed high production anime films.
Ghost in the Shell's story of questioning your own identity as well as its dreamlike establishing segments had a major influence on the Matrix as well as many other films in sci-fi and beyond. And that's not even bringing up Satoshi Kon's works with time and the border between fiction and reality that influenced Darren Aronofsky among others.
While Shawshank Redemption and Forrest Gump are good films, they are contemporary works. They fit perfectly into the genre and time period they were created in, never breaking any new ground or doing anything significant artistically. Don't get me wrong, this is probably why they are so beloved, because they appeal to the absolute majority of people, hence why I call them classics rather than influential.
Personally, I can't think of a single film that either of those films have had any major influence on, and I doubt they've changed movie making as a whole. Possibly Forrest Gump's impressive CGI, but even then Independence Day had a larger influence on 90's-00's CG and I wouldn't call that an amazing work of art...
Boy that became way too long, I love ranting about movies.
Anyway, tl;dr: Those are good movies, they just aren't that ground breaking.