As I posted in another thread
I hope this film is awesome since it will give Fox leverage to get Marvel to stop playing hardball and work out a similar deal that they worked out with Sony and Universal.
IMO, the best way to merge universes is to do House of M at the tail end of Phase 4. Have Doom tempt Wanda with a world where her brother is alive and have her remake reality so the Avengers are now in a world with the FF and the past and present X-Men where Magneto rules the world with Doom looking to usurp.
The end result is that there's now a new universe when reality is restored with only a few continuity fixes and for the most part, all of the First Class and MCU timelines happened. We get Fox-Men Quicksilver and MCU Scarlet Witch.
Also, when reality is restored, Norman Osborn is director of SHIELD, The Negative Zone has opened up into our universe and Red Skull is Germany's representative on the World Security Council.
Phase 4 should be a breather episode where classic stories get retold and we see more character development, films are more stand alone and important side characters are introduced.
Phase 5 is Dark Reign where the stakes have never been higher, the villains have won and we see the heroes holding on for dear life against impossible odds.
Fox will maintain creative control but Marvel will have to approve all scripts and casting choices.
Phase 5 films will include
Guardians of the Galaxy: Annihilation
Spider-Man: The Night Gwen Stacy Died
Iron Man: World's Mot Wanted
Captain America: Red Zone
Hulk: Code Red
Black Panther: Enemy of the State
Captain Marvel: War of the Marvels
Thunderbolts: Dark Avengers
Doctor Strange: Darkhold
Thor: Gods and Men
Mighty Avengers: Siege
And then culminate with West Coast Avengers: Kang Dynasty where after Norman Osborn is unseated at the end of Siege, Kang conquers the world, being yet another side-effect of Wanda's tampering with reality.
That's why I want this film to succeed. There is nothing about this film that isn't salvageable in a sequel and if Fox and Marvel can agree to merge universes while maintaining continuity, all the better.