I'm still unsure as to whether Thanos will definitely be the big bad in Avengers 3...
With so many new characters being introduced over the course of Phase 3, I think the third Avengers film should give us an opportunity to focus on the new team of (most likely)...
Scarlet Witch, Quicksilver, Vision, Ant-Man, Dr Strange & (possibly?)
Wasp
...Whereas I think a face-off with Thanos should, and will, feature multiple teams so as well as the above and the "Guardians Of The Galaxy"
(Starlord, Gamorra, Drax, Rocket & Groot) we may also see a "Secret Avengers" team of
Captain America (either Steve Rogers or Bucky Barnes depending on how Cap 3 pans out),
Falcon, Black Widow, Sharon Carter, Maria Hill and Nick Fury.
War Machine/
Iron Patriot wouldn't be out of place in that line-up either, but I've a feeling that someone like Strucker or Zemo is going to get their hands on that Iron Patriot armour as we aren't going to be getting Norman Osbourne any time soon but he was a big catalyst in many storylines of the past decade that seem to have, along with the "Ultimates", influenced the MCU just as much as the "classic" stories of the 20th century.
I'm not sure about where they'll take
Hawkeye, but I'd like to see
Mockingbird brought into the mix and it would also be cool to see him in his
Goliath and
Ronin guises at some point.
Speaking of Ronin .... I kind of get the impression they've had a look at the New Avengers & Defenders rosters and come to this conclusion...
Two of the original four Defenders (Silver Surfer and Some say Namor)aren't available, and another (Hulk) is already around in the Avengers (though rumour has it that may change at the end of Avengers 2)...which just leaves Doctor Strange, who was also on the New Avengers roster so how about a "New Avengers" line-up?...
...Well looking at the New Avengers team, you've got a couple who can't be used (Spidey and Wolverine are with Sony and Fox respectively), a couple who're already in the Avengers AND doing their own thing (Captain America & Iron Man) , and a handful whose power level is more suited to the small screen (Luke Cage, Iron Fist etc)
....... soooooooo whaddya do?...
...Feed Doctor Strange into the main Avengers team along with the late 60s/early 70s recruits also being brought in because his power level fits more with the big screen than the small and there isn't currently the opportunity to roll out the classic Defenders line-up...
(in fact, I wouldn't be surprised if we get an appearance from the Scarlet Witch in Strange's solo movie giving him an Avengers connection prior to Avengers 3)
... that leaves the "Defenders" name on the table whilst at the same time you've got a handful of characters associated with the New Avengers stories such as
Power Man & Iron Fist, Jessica Jones, and to some degree
Daredevil looking for a flag to fly under in the miniseries that sets the team apart from the big screen "Avengers".
So the "
Secret Avengers" get Cap 2 & 3
The
"Defenders" get their Netflix miniseries
"Guardians Of The Galaxy" get a movie or two, (possibly bringing Hulk back to Earth after a take on the "Planet Hulk" storyline)
...so our "New" Avengers team would be overshadowed by other more established ensembles were Avengers 3 to be the Thanos story ... they need a movie of their own first, and that is what Avengers 3 should be
This is why I believe that Phase 4 will build up to a
"Marvel's Infinity War" , or similarly titled movie,which will essentially be both
"Avengers 4" AND
"Guardians Of The Galaxy 3" and will give us a big showdown with Thanos featuring the whole of the MCU, and in which we will also see the reunion of the "big three" with Stark getting back in the armour, Steve Rogers returning from "the dead", if as I suspect they are going to follow the Brubaker run up to the "Death Of Captain America" in Cap 3, and Thor returning to Earth after serving time on the throne of Asgard following the end of his trilogy which I think might feature elements of the "Loki" graphic novel amongst other things.
...and just for the cherry on the cake I'd give
"Director Coulson" of SHIELD an appearance as well, and I've no doubt he'll be seen on the big screen again at some point, albeit in a cameo
