Alba and the guy that played Doom were completely miscast.
No argument there whatsoever. Alba seemed to be cast based exclusively on how good she looked in her underwear (which is pretty much the extent of her qualifications as an actress). Maybe that would've been okay for Sue as she was portrayed in the early '60s, but the modern Susan Storm-Richards is just so much more than that -- a gifted superheroine, a superb mother, the heart and soul of the Fantastic Four, an intergalactic diplomat of great renown, etc.
I'd kind of like to see Fringe
's Anna Torv as Sue. She has the combination of strength, intelligence, dignity, and warmth that the character needs. Let's not do another origin story with a young Reed and Sue -- let's see the team already established as the royal family of the Marvel Universe, with Reed and Sue as accomplished, globally important figures balancing their responsibilities to the world and the universe with their efforts to raise the two most gifted children on the planet.