What series with Dr Doom have you read?
I've only read The Books of Doom and Secret Wars in terms of Doom focused stuff. Most of my exposure to the character was in mainline comics and reprints (Fantastic Four) in the 70s and early 80s - and I think Doom is a GREAT character, my point is that there's basically no way to make the things that resonate with him in the Comics work in a mainstream marvel movie UNLESS it's a comedy.
Doom's appearance is ridiculous for a mainstream audience and the nuance of his narcissism and cleverness I think requires a big investment from readers. Maybe the Doom standalone movie could work, but the only way FF4 can work, IMO is full Ragnarok/Galaxy Quest treatment. Admit it can't be serious and relax and have fun with their goofiness. And that won't make the right things about Doom resonate with fans, unless they tell the FF4 story from his perspective (like Despicable Me).