Warning: The following article may include some mild spoilers for The Avengers.
Warning #2: This is hugely nerdy.
It all started with Thor, last year, which expanded the shared universe to include alien worlds and alternate dimensions. The Avengers blew the universe wide open with the introduction of more alien races and their god-like alien puppet masters (I struggle to consider this vague description a spoiler because it is literally the first scene and will only have significance for comic fans).
Now that audiences are prepared to accept a wider Marvel Universe, not just the Earth-based heroics, Kevin Feige is seriously considering the idea of bringing some of Marvel's more ambitious and untouched properties to movie audiences.
Speaking to Movieline, Feige confirmed that they had now made every film they originally intended to make but now that their first phase is over, thoughts were turning towards new challenges.
“We have! I mean, there are certainly others like Guardians [of the Galaxy], like Inhumans, like Doctor Strange that we haven’t yet, but I am confident that we will. So there’s a lot of satisfaction now, on the eve of Avengers, that this thing that was deemed impossible has actually occurred.”
The original Guardians of the Galaxy were introduced in 1969 as a group of alien superheroes who defend the 31st Century of an alternate universe, but was relaunched in 2008 within the official Marvel continuity (known as Earth-616, to fans).
This is likely the version Marvel will adapt, as it's not only directly tied to the worlds and characters introduced in Avengers but it has the more marketable roster of characters. Names like Star-Lord, Adam Warlock, Major Victory (a human astronaut propelled out of time and space, this would be the obvious choice for an audience surrogate), Drax the Destroyer, Phyla-Vell (sister to a certain fellow called Captain Marvel, who could also find himself introduced in such a series).
Slight Avengers spoiler, one that is only relevant to comic fans: The series also stars a character called Gamora, who is the daughter of Thanos, the secret antagonist of The Avengers revealed in the mid-credits tag, suggesting a bigger role in the sequel. Introducing a character directly tied to Thanos would be a great way to lay the groundwork for a company-wide crossover that will make The Avengers look like Adam West's Batman.
The use of key characters in Guardians of the Galaxy could serve to introduce the Kree Empire, a major player in the wider Marvel Universe. This would lay the groundwork for Inhumans (which Feige also referenced as a title of interest), a race of genetically modified humans, created by the Kree to help in their war with the Skrull.
Note: The Chitauri, the punch-fodder villains in the Avengers movie, were the Ultimate Comics equivalent of Skrulls but are so far removed from their original design that Skrulls could still be used in future, in a more fleshed out manner.
While Marvel continues to expand the cosmic aspect of their movie universe, a Dr. Strange film could see them expand into the supernatural. Strange is a master sorcerer and one of the most powerful heroes in the universe; he would also open up even more possibilities (and threats) for this shared world.
Movie audiences are now willing to embrace the bigger, wilder aspects of the superhero genre, we are a long way from X-Men's dialed down, gritty aesthetic and we could see trends move away from the serious Frank Miller or Alan Moore style movies and back towards the more fantastical worlds of Jack Kirby or Walt Simonson.
Before Marvel can expand on this hugely ambitious task, we will be seeing more familiar projects with Thor 2 and Iron Man 3 on track for release next year and Captain America 2 locked in for 2014.
We still need to see Ant-Man and maybe a Black Widow/Hawkeye spin-off but there could still be room to include a more cosmically inclined movie, to help set the stage for The Avengers 2.
The Avengers 2 is likely due for release in the summer of 2015.