My beef with the Fox adaptations of the Fantastic Four (done in three separate movies) is that they made Doom a kind of comic-relief villain (and the Thing looked terrible). In the third adaptation, they also decided to continue with an origin story and origin stories always end up bad (and it once again lashed Doctor Doom to the origin of the Fantastic Four, which I don't like). I also felt that Michael B. Jordan played the role of Johnny Storm too serious. Johnny is an incredibly immature character, and you have to have an actor that is essentially a "Peter Pan" to kind of nail him right.
In a rewatch of Avengers: Infinity War, I discovered that there was at least one line that I thought could possibly be an Easter Egg for the fact that Disney was pursuing talks with Fox Studios in obtaining the rights to the Fantastic Four. So I did a google search and saw if other people had come up with any others and the following is my list:
1) When the battle with Thanos's minions gets started in New York, Tony Stark (while talking with Doctor Strange) refers to one of the bad guys as "that rocky thing there...." It could be just a way of describing something, or it could be a way to allude to The Thing.
2) During a lull in the fight on their way to meet Thanos, Draxx is trying out a new power, hoping that by staying perfectly still, he can turn invisible. It's very funny, and I think may be a call out to The Invisible Woman.
3) When Thor is forging Stormbreaker (his new weapon), he screams, "Flame On!" as he asks to get the works hot enough to do what he requires for the forge to work. I think this may be an Easter Egg for Johnny Storm, a.k.a., the Human Torch.
4) When we first see the Guardians, they're rocking out to "Rubberband Man" from the Spinners. This could allude to Mr. Fantastic, right? If you follow my logic, sure.
Anyway, the MCU should at least mention the country of Latveria (where Doctor Doom is from) even if it is a headline on a TV news report discussing the Latverian ambassador's outrage over something. With the MCU already having gone cosmic, it would be so easy to sneak the Silver Surfer in there as well. And if they introduce the Silver Surfer, then maybe we will finally get a peak at what Galactus has been up to, which will give us the next big bad for all the characters to team up against.