This is what I would like to see as the Marvel Cinematic Universe Phase 4. None of this has been confirmed and this is a personal opinion.
This one has been confirmed, and I think it will be a huge game changer, having people with crazy powers in the Marvel Universe now. I would recommend Maximus the Mad as the villain.
Guardians of the Galaxy 3 (2020)
Not only would this movie be hilarious and complete GOTG's trilogy, I also think that if Nova is not introduced in Phase 3 then this would be the perfect time to do it. I'd pick the Skrulls as villains but I'm not 100% sure who owns them.
[Black Panther](movie:9047) 2 (2020)
I don't have much to say about this movie, judging by the fact that we've never seen him on the big screen.
Captain Marvel 2 (2021)
Again, since we have not seen [Captain Marvel](movie:949779) yet, I have nothing to really say about this.
Spider Man 2 (2021)
I think this movie should (along with the first) have the same costume and special effects from TASM2 but create a much better storyline. For the first Spider-Man I think that Doc Ock would be the perfect villain, so for this sequel I'll have to put down either a better version of Venom, or Kraven the Hunter
Scarlet Witch and Quicksilver (Late 2021-Early 2022)
I think Marvel could do so much with these two surprisingly deep characters. Their array of powers and abilities are some of the most impressive in the whole MCU and I think that a solo movie with them would be great fun. The only problem is the villain, but I'm sure that Marvel Studios could find one that worked.
Captain America 4 (2022)
This movie would star Bucky Barnes as Captain America, and I think just the idea of that alone would make millions of dollars. They could easily use Baron Zemo as the villain and make an entertaining, thrilling espionage movie kind of like CW:TWS.
Planet Hulk (Late 2022)
This has been a seriously anticipated movie, and I think that seeing an all-Hulk romp fest would be absolute fun. Mark Ruffalo himself said that he would defiantly do a Planet Hulk or WWH movie were he did almost all MoCap which I think would be fun, violent, and a new side of the character we've never seen before.
Ant-Man 2 (2023)
I am highly looking forward to Ant-Man this July, so who wouldn't want to see Ant-Man fighting alongside the Wasp one more time? Villain: I don't know much about Ant-Man villains...so...
World War Hulk (Late 2023)
That's right: instead of a climactic Avengers film I am putting down World War Hulk. Who doesn't want to see Hulk fight the WHOLE MCU?! And since most of the big-name Avengers will be dropping out after Infinity War, why do we need an Avengers movie at all? Just have them all fight together against a former friend? Plus this would also be a good time to bring in an old Tony Stark to help mentor the younger heroes on how to fight/defeat the Hulk in battle (Seems like he will be fighting ol' greenie this May).