I enjoyed this version a lot. It doesn't compare with the original, which I saw on TV when I was about 10 and which made me fall in love with Westerns, but it looks great and has some engaging characters and spectacular action scenes. As someone noted above, you could regard it as a belated follow-up to Return of the Seven, Guns of the Magnificent Seven and the Magnificent Seven Ride rather than an actual remake. Only the scene where the James Coburn equivalent is recruited approximates to the original, though we do also have a gunman who's lost his nerve (with an interesting backstory of respect between an ex-Confederate and a former slave). It does borrow a couple of lines of dialogue from Sturges's film (which is one of the most quotable of Westerns), but not the wonderful last words.
As for the influence of other Westerns, I'm sure that Denzel Washington's first scene was directed with High Plains Drifter very much in mind.
Though I enjoy a full-on shoot-out as much as anyone, I think you actually get too much of a good thing here. When the Seven first arrive in town, they take on a handful of crooked deputies, but the foes keep on crawling out of the woodwork and the final body count is about 22. It's a great action scene but you can't help wondering "where did that lot come from?" Similarly, the final showdown, though excellently choreographed, just goes on and on. There are only so many ways that heroes can shoot acrobatically and villains can collapse. I was actually reminded of Savona's A Man Called Apocalypse Joe, an enjoyable minor spaghetti where the final shoot-out goes on for about 40 minutes, suggesting that the script writers had run out of ideas (though there are some nice, witty twists in that one).
Also, the villain's Native American henchman reminded me of Ronnie Barker in that Two Ronnies "Red Indian" sketch. Sorry to have to plant that in your heads, UK readers.