Fox has so far made 3 The Fantastic Four movies, all of which people consider a worthless cloud that vaguely made the Galuctus head shape in outer space. But, because Fox for some reason wants to keep the rights to the Fantastic Four they should consider using villains other than Doom. It's the Superman movies all over again.
With the introduction of a villian like him it could show that the FF exist in a bigger universe. The Fantastic Four are mostly cosmic heros that travel the universe and we haven't seen that part of them. I mean we kinda did with that Amazing reboot in 2015! But with annihilus they will go to places other than a rock world filled with lava. The Negative Zone! Also he looks really cool.
2: Super Skrull!
The FF meet their match! When shape shifting mini green thanos's invaded the earth, one of them got all of the powers of the Fantastic Four! This is a great idea unless the Skrulls are owned by Marvel. He would also sell a lot of toys because he is visually interesting! Because Fox is all about making money! That's their #1 priority!
3: A proper Dr. Doom!
I know I said not to use him but who wouldn't want to see a proper Doom? So far Doom has been a business man and a blogger. How threatening! Doom is one of the most powerful and awesome characters in Marvel and they have messed him up twice! Don't make him part of the FF's origin! Just start the movie, have him show up, then have Reed Richards say he knew him in college. Make him like iron man but also with magic! It's that simple! You could even have him look like he did in the 2015 reboot!
I'm just kidding, just kidding! Maybe I'm not?! The internet is a scary place. What the hell where they thinking?
4: The Mole Man!
See what I did there? 4 villains! Any who. The mole man was the first antagonist of the Fantastic Four. I'm sure all of you know that but I'm saying it anyway. A disgusting little fellow, he could be like Loki in The Avengers! Making his evil plot to make his army rise from the ground!