So many memorable lines and high points - that's what makes it a classic - along with a monster cast, even for its' day. Everything in the way of sequels and remakes that have followed have been pathetic attempts to cash in on something that couldn't be replicated since the bulk of the original cast was killed off in the plot of the first.
Part of the appeal of the story is multiple strong characters that you get insights to about their personalities and behavior. I think it would be difficult to capture that same "something" that distinguishes this film today. Not just for lack of stars that compliment each other, but in the overall tone of the movie and how you wind up feeling about the characters.
There was just something 'huge' about movies like that back in the day of their release that I don't get the sense of these days, no matter how much hype and advertising is done to set up the audience's expectations. One of the many films that was witness to the end of the era of the true "stars" based on great work instead of a press package touting the "impressive acting skills" of people you've never heard of.
I first saw The Magnificent Seven on the big screen at an outdoor theater - "larger than life" for sure. That, along with such a memorable musical score and being an impressionable kid raised up on TV westerns and . . . Bingo - instant memories.