Yeah, the choice to make Watson a woman seems like this is going to be like Moonlighting. If Sherlock were the asexual neurotic cokehead he is in the books, he wouldn't be as marketable on CBS. Which is too bad, because Sherlock's "freakishness" is what makes him a cool character. That's the thing the BBC series really got right--that Sherlock and Moriarty are these two guys who think they're gods, and that they're separated from the rest of us "normal people".
A coked up loner genius going on adventures would be a show I'd watch.