Ian Fleming himself wasn't particularly pleased with Sean Connery as Bond, as he didn't fit the character described in his books. Though, he eventually warmed to Connery's interpretation, and even gave Bond some Scottish heritage in his later works.
It's an interesting proposal. Can the character of Bond, the womanising secret agent who's seduced almost every woman he's ever met, be a gender netural role when it's so strongly defined by Bond's own status as an 'icon' of masculinity? I don't know, but casting a woman would certainly shatter this perception.
I'd find it difficult to rank Bond on par with the likes of King Lear or Richard III, particularly since his presence in contemporary culture has embodied stereotypes which have been so intrinsically linked to his characterisation. If Gillian gets the part, and it isn't a 'stunt' as Mads describes it -- I'll be intrigued to see how they handle these issues while still embodying the traits which have defined Fleming's creation for so many years.