I would loathe it. Not everything cool in Marvel needs to be given to Iron Man. Let Doom actually be an FF villain. Don't pawn him off to the Avengers just because Stark! I want Doom and Reed to be rivals and former friends. The FF help make Doom what he is. USE IT!!!! Making Doom basically an Avengers villain and limiting his FF ties would make me care far less about seeing him in the MCU. I want to see Doom as a proper FF villain before they start branching him out. Unless it is a cameo or something small. But starting him as an Iron Man villain? Crap.