It's not the script that makes this movie great... but it's great nonetheless

Rating: 9/10 (14 April 2014)

The Avengers is a great movie, but not due to its plot. It's a simple MacGuffin chase, culminating in a random big fight. Also, the editing felt unfinished from time to time.
Nevertheless... it's not the plot that is supposed to make the Avengers a great movie. It's the fact that it brings stories and characters from other movies together. In a way, the Avengers is the finale of a bigger whole.
The lack of plot gives the opportunity to zoom into the different characters and how they respond to each other. We learn how Bruce Banner and Tony Stark connect. We see how The Hulk and Thor have a measurement of strength. How the straight morals of Captain America conflicts with the happy go lucky attitude of Iron Man.
We also get a closer look at SHIELD and we learn that the agency has its moral questionabilities. When we move beyond the Avengers, we learn how that is so in Captain America: The Winter Soldier.
The choice for Loki to be the main villain connects to the firs Avengers comic. And in many other ways as well , the movie pays its respect to the comics - as we're used to in the Marvel Cinematic Universe (MCU). The Avengers movie is a mile stone in the MCU, and yes, its greatest merit is being the Avengers movie.
It's not the plot that makes this movie great. It's the fact that it's the pay-off for earlier established characters and stories, and laying the ground work for more great stuff to come.