I've always liked the male friendship that Holmes and Watson have with each other. Making one of them a female completely changes the dymanic between them.
First off, who says? Men and women can have great friendships with each other. After all, Holmes is a rather asexual character, so as long as you write out his ingrained misogyny (which is a given for a modern update), it wouldn't really make any difference.
Second, have you seen Steven Moffat's
Sherlock or Guy Ritchie's
Sherlock Holmes movies? Holmes and Watson are both male in those, but both versions are drenched in homoerotic subtext. So no, I don't agree that having a female Watson would fundamentally change the dynamic any more than other adaptations already have.
Third, if it does change things, what's wrong with that? We've had countless conventional adaptations; what's the point of doing another if you don't bring something new to it? I mean, think about it. This is a Holmes adaptation set in the present day in New York City.
Obviously they're not going for a rehash of what we've seen before. I'll never understand fans who consider it wrong for adaptations to change things. The whole
point of adaptation is change. There's no sense in doing a different version of a story if you're just going to copy what the original version already did; that's a complete waste of time. The point of doing an adaptation is to find a new approach to the concept, to develop a different aspect of its potential.
Fourth, Lucy Liu is cool.
She even warmed Bender's heart. And it's always refreshing to see Asian actors cast in traditionally white roles, especially these days when the reverse seems to be disturbingly commonplace in Hollywood.