Thanks to John Parker for this idea in a comment from this article's original one, which you can read from my page
Fantastic Four in the MCU
This too sounds intriguing. They can cast anyone they want, there hasn't been a very popular, recent, high end movie in their franchise, and as such, their branding to the general public is null. They could as such take anyone they wanted and make them Marvel's own brand of awesome.
I decided to break down each character's dynamic if introduced to the MCU. Johnny Storm. He can light himself on fire and fly unpropelled. And he just so happens to be just like Tony Stark. The two would get along quite well, and would have fun along the way. The rest of the team, like F4, might have a problem with his antics, and he might get in some trouble. Overall though any evil stopping team needs someone who can just wreck all out. Welcome, Johnny Storm.
Though not a total disparity, there is a lack of totally hot bad-ass woman currently in The MCU. Though most of the team will be a little annoyed that their gorgeous new addition is married, they will certainly be happy to have someone in stealth mode, and someone who can throw a block if they need it to.
Dr. Reed Richards
Here is someone who may cause a bit of discord amongst the ranks. There is a ton of intellectual firepower already involved, and adding another layer might cause too much of a problem to be a healthy fit. And with the kind of intense large scale battles The Avengers are used to, the ability to stretch May not be the most helpful tool. In fact the limbs may almost just get in the way.
He is yet another perfect match, someone with guts and generally a pretty smooth guy emotionally he can be a literal rock on the team. I could certainly see him having some fun with Hulk, like maybe Hulk picking him up and hurling him at an opponent, or maybe a small battleship. Either way he could be a beast for the Avengers.
Though maybe a bit emotionally rocky, they could certainly be an awesome addition to the MCU