Okay, Julian Mcmahon SUCKED as Doc Doom.
IF, hypotheticly speaking, someone 2 years up the line decided to make another F4 movie, reboot or no? How could you portray the character of Doctor Doom?
I think it would be good to have him as, yes, an internationel Billionare. Maybe no strong german accent, but definatly more definatively European. And he is funding Reed's trip into space, not to get rich off it, but to study the affects the metal of their craft is effected by the storm, then use the energy trapped in the Metal (Vibrainium, it absorbs it like a sponge) to make a new bread of weapons, and Armor. The Four return, superpowered and well. And this puts a crink in Doom's plans and has to work even faster to finish his deals, (With people that turn out to be HYDRA or AIM), because the F4(with the blessing of SHIELD) are following leads and discovering their over exposer to the cloud was no accident. As Doom begins to experiment with the materials for times sake, the cosmic properties change him. Not dramaticly like giving him electric powers, but maybe metalic bone marrow like in the ultimate F4 comics. Enough to portray how even though he MAY have super human traits, his biggest threat is his mind. He also begins to take it into his head how with the properties the Cosmic
cloud, he could actually go on his OWN campain with his weapons. Maybe even rule the world, since he's the only one who understand the matrix of the energy, well.....him and REED. Thats why Reed HAS to go.
As a measure of last resort tries to lure them into his trust, Sue and Johnny anyway, and Use Reed and Ben to power his new weapon, "The Doomsday" with their cosmic energies (Their life force). It is hear that the 4 and him do battle, him wiht his cosmic powered, vibrainium suit, them with their abilities.
The movie ends with the destruction of his Doomsday machine, and Dooms alowment to remain unincarcirated because his in Latverian juristiction.
As for who could play him, a good actor like: Dougray scott, or Rufus Sewell
Someone who can really portray the personality and air of Victor Von Dame(also prononced DOOM)