Godfather has died out in relevance, just like the actual Italian mafia.
Scarface (as much as I LOVE this movie, and believe me I LOVE IT), I must say that it'll be outdated soon enough. I saw it just the other day and certain parts don't hold up. Tony Montana simps for Michelle Pfeiffer's crack-hoe looking ass. He could've married a beautiful cuban chick with all the drug money he was making. The movie was a cultural success in the black and latino communities in America and probably inspired a lot of real life gangsters to pursue the life of crime. But it's hard to ignore that Tony Montana made a lot of stupid decisions in the movie, it's hard not to watch it these days without facepalming. Half the time, you just want Tony to calm the fuck down so he doesn't say something stupid that would be used against him in a court of law. Also, drug gangs are becoming less and less popular. The mentality of gang culture that Scarface portrays is not sustainable in the near future.
Avatar was pretty to look at. If the movie can be visually enhanced for future viewing on the latest technology, like VR, then I can see the movie standing the test of time. In terms of storyline, it's nothing special.
John Wick 1 was a good movie, a REALLY good movie. However, John Wick 2 wasn't as great as the first. The 3rd movie was just fucking silly, dear God. At this point, everyone and their grandmother is an assassin. Let's get real lol. John Wick 1 will probably would've had the highest chance to stand the test of time, but the sequels ruined that opportunity.
Avengers? Are you talking about the first Avengers movie, or Endgame? The first Avengers was a BIG fucking deal when it came out. Years of planning and execution done right. Same with EndGame. Years of planning and execution. Future generations will not be able to appreciate how much work was put into this cinematic universe because they haven't lived through the hype of watching new Marvel movies and building up the excitement for the inevitable Phase 1,2 and 3 Avengers films.
Honestly, I'm gonna have to go with Avengers Endgame on this one. It's just a marvelous piece of action (pun intended)