Loki would have totally ruled. Instead of mind-controlling Hawkeye, he would have just gotten an army comprised of ‘soldiers’, ‘lieutenants’ and ‘pyros’ and sat back and watched as they one-shotted the whole Avengers squad while giving him unlimited power.
If avengers movie was like MPQ rags and Loki would have destroyed every1 in the 1st 2 scenes.
The hot dog vendors would make a lot more money.
Hah! I laughed out loud at this and woke my wife up. 
Not likely given how expensive the hot dogs is and how ineffective it is, i doubt any of our hero would buy a hot dog. They would rather go to the forest and stab them self with thorn rose instead.
…the Avengers would have joined forces with Loki to create an even stronger alliance. But first, Nick Fury would have to spend money to add one more seat on the Quinjet. 
Then Loki would have promoted himself to commander and ‘tricked’ everyone else in to leaving.
He’d remove people and told people that Nick Fury did it.
…it would be called The Captain America Movie.
Captain America vs the Environment!
So true.
Hawkeye would be fired to make room for a better hero.
Black Widow would be given a mask so she can sneak around and steal enemy assets.
He did try that, only he brought the army in inter dimensionally. He even had multiple modern equivalents of devil dino that could fly.
Unfortunately he faced a newly assembled avengers team so they had scaling in their favour. We didn’t see the X men because they have been around for years so all the chitauri were 230s.
and if they make a movie based on the past 2 weeks it would be called Headbutt
Brought to you by Unstoppable Films Inc.
Then the Chitauri would be pissed that Loki pulled Thanos into his alliance when he was with them first.
Scarlett Johansson would be in fishnets…
If the avenger movie was like MPQ it would have spider man in it.
I liked this one, I snorted after reading it.
I suppose I should try…
Black widow would have a costume change that affected her fighting prowess…
Nah, I got nothin:P
Edit:
Black widow would shoot 3 aliens with one sniper rifle shot.
…Iron Man would have stunned himself right when he tried to deliver the bomb into another dimension.
…Hawkeye would make all of his teammates take double damage just for lulz.
…Nick Fury would have gotten a different actor mid-movie.