The sweet spot exists because a different image has to be sent to each of your eyes. I don't think it's possible to make the sweet spot any bigger than the angle between your eyes without some crazy-sophisticated setup.
"The worst part about these reviews is they are [subjective]--and their scores often depend on how drunk you got the media at a Street Fighter event." — Mona Hamilton, Capcom Senior VP of Marketing
*Image indefinitely borrowed from BrainBoxLtd without his consent.