Bruce Banner is a physicist, or perhaps a biophysicist. He's not an engineer and he's never designed uber weapons. This like having Tony Stark invent a way to cure the Thing even though Richards has never been able to do it. Doom has all kinds of knowledge regarding force fiels, EMPs, and all the other standard tech that accompanies using sophisticated armor. No way should it just be shutdown like that. I wouldn't be happy if Reed did this. Perhaps because of his speicality I could see Stark doing it, but not given what we've seen in continuity. Doom is better than this.