I assume that you all know the immediate problem with that, yes? That’s right! It’d require that Fox do a Doctor Doom movie. GeekTyrant is excited about this, on general principles; and I’m not saying that Mads Mikkelsen couldn’t do a good job as Doctor Doom. He absolutely could. I just don’t see how Fox can be relied upon to produce a decent Doctor Doom flick.
Also… who would Doctor Doom be facing in a standalone villain flick? The Fantastic Four are owned by Fox, but they suck at making F4 movies. This is known. The future of the X-Men is kind of up in the air right now, and they’re not really associated with Doom anyway. Spider-Man is owned by Sony, and in the loving embrace of the MCU right now. The Avengers are MCU (Fox should make a deal with Marvel/Disney), and Namor is apparently back at Marvel (Fox should make a deal with Marvel/Disney), and Squirrel Girl* always was Marvel’s (FOX SHOULD MAKE A DEAL WITH MARVEL/DISNEY). I will freely admit that I may be missing somebody, but that sounds like most of the major heroes associated with Doctor Doom.
And if he doesn’t have a worthy opponent, well: what’s the point? Doom would just be this guy in a permanent metal suit who is almost as competent as he thinks that he is. This is not exactly exciting cinema.
*Also: you can have a movie where the villain wins, or you can have a movie where Squirrel Girl is your opponent. You are not allowed to have both. It’s one of the more obscure laws of physics, sorry.