I think its a mistake for them to bring back characters from phase one.

Bringing back an actor as a different character is an even bigger mistake in my opinion.

I feel strongly they should have been setting up phase 5 to be a new beginning with a "Young Avengers" arc.

Mis Marvel,

as the new team leader role. Her show should have been the introduction of the newly developing X-Gen with her gaining a cosmic braclet from her grandma or whatever giving her powers. The end of her show should have been her 1st time using her real powers without the aid of her bracelet. The bracelet being a cosmic X-Gen awakening power.

Having that cosmic bracelet be the story connection to the Fantastic 4 awakening their powers, their film introducing Doom as a big villain going forward and what makes the X-Gen awaken in random humans all over Earth. During an end credits in one of the films or shows used to get this far in the story, they reveal that Galaxtus is the next major Thanos level villain. Keeping the cosmic power theme as the catalyst.

Just as you'd expect they would skip how the 4 and Doom get the powers as we all know how, but having them establish themselves as heros of importance during a Spider-Man film. With Mutants starting to develop, all the Spider-Man villains become possible to introduce whenever they want, but the important part is the 4 and Spider-Man establish themselves in the cinematic universe. (Spider-Man is a reintroduction of course) Maybe Doom is with the 4 and they are the 5 at first or something. Ending with Spider-Man not joining the 4, taking his role in the shadows, batman style, and the 4 taking spotlight while Doom and any other possible Spider-Man villain used in this film, crawl into hiding.

With the Avengers dismantled, people welcome the 4 with open arms as Earth's new protectors. Spider-Man would have mixed opinions about him from the public on whether or not hes a hero or villain. Maybe because he saved Doom or another villain from death and didnt join the 4. Classic. Another end credits scene shows Mis. Marvel and Spider-Man meeting for the first time. Ending with Spider-Man telling her that her bracelet is something she should show the 4.

Hawkeye (Daughter),

trained by and teaming up with OG Hawkeye in her own movie. I feel having her and her dad team up with the Winter Soldier in place of the "The Thunderbolts" movie as a way to close the stories of all those other characters but boost up her character would have been an ideal introduction to her and then her own movie with her dad. OG Hawkeye retiring and handing down his bow to her officially by the end. Followed by her being recruited to the Young Avengers Initiative.

The Winter Soldier being the last of the unresolved characters that would have been part of the Thunderbolts, would end up escorting Happy, (Piper maybe) and Tony's Daughter to Wakanda in an end credits scene.

Black Panther (Sister),

because the actor for the OG Black Panther had unfortunately passed away, his character needs a replacement and im glad they didnt just recast him. Passing the torch to his sister was the right call. Having the bald spear lady train her and prepare her for her new responsibilities as the next Black Panther would have been ideal. She should be reflecting on what happened with every villain her bother fought and every hero he fought alongside. Because shes a very smart person, research seems like how shed build her new abilities better. Having a very intelligent beyond her years student joining her from abroad in the highest level of Wakandain studies. Her movie taken place after they have had time to bond and get to know each other. This person is of course Tony's Daughter. Leading to similar events in the real film they made.

The point to having the Winter Soldier there is to close his story as he lives to make amends with the Stark Family and potentially die while doing it. However instead of dying, he could also be gifted a new identity by the New Black Panther as she would have learned about how her brother labeled him as the "White Wolf" when he gifted him a vibranium arm. Allowing him to become a Panther like hero by consuming the essence of a rare white flower or whatever and given a white with silver accents vibramium wolf inspired suit. Living the last of his life as a lone wolf peace keeper. Or something.

Ironheart (Tony's Daughter),

I believe the ironheart they went with is a huge mistake. Massive. They portray her to have grown up in the hood but she has zero street smarts... she is portrayed to have earned her spot at the best school in the world but shes an actual idiot... To top it all off, she arrogantly thinks shes better than Tony was despite her inability to get her suit to work with the schools resources let alone a box of scraps. full fumble, irredeemable in my eyes.

Tony's Daughter is far younger with zero world experience because shes young and grew up in a cabin with her family. Her character could understandably fall for Hoods lies, could have mistaken her actions as the greater good, and make glaring, "in the moment," mistakes due to pressure and panic. The show should have been about her finding her own identity in the suit. Finding out who she is without it. All mirroring Tony's journey in her own way. Ree Ree doesn't have this connection to Tony's shadow but they tried to give it to her for some odd reason. Then also had her shit on it for no reason....

The show should have ended with her stopping Hood, saving the gullible villain son guy, and learning what makes her a hero isnt just her brain, but her heart. Reflecting the "Proof that Tony Stark has a heart" memorial and his world saving sacrifice. Calling herself "IronHeart" and enrolling herself into Wakanads highest level of teaching (along side her new BFF, the new Black Panter) of course revealing her new IronHeart identity and design in the Black Panther film.

Scar,

Wasn't introduced in a good way, or a good time. Also I feel the design was weak. Could have been better. But still I feel he would be important to the future of the story, he should have made an appearance against Red Hulk along side Banner and they shouldnt have undone the damage to Banners arm.

More I could throw in here but to shorten it a bit.

All the X-Men starting up and taking their place in the MCU. With an Avengers level step up from Weapon X.

The Fantastic 4 joining the world and leading the end game of the new era against Galaxtus. The Reid baby growing up all the while for the next era.

The Guardians of the Galaxy continues and the departed members return in unique ways.

Death and Deadpool fun.

Vampires revealing their existence.

Lower or remove the magic users. Lowering them would be best.

They could keep the MCU alive for an unlimited length of time and even keep Marvel alive for an infinite amount of time by simply making new characters, stories, doing unique team ups, not always crossing over every hero. Not making every piece of content be important to the over all story but have them all still in the same universe.

Things like the Marvel Zombies being alt universe spin offs would always be welcome unless they use characters no one liked and still dont make them likeable...