While I don't have great expectations for this show, the casting of Lucy Liu as Watson DOES strike me as a pretty interesting one.
After House, Sherlock, and the RDJ movies, the previous dynamic feels awfully played out by now, and having a woman in there could provide something new.
Of course, as usual, it all depends on the writing.
This is actually not
the first time Dr Watson has been a woman in a network TV updating of the Holmes story, interestingly enough. There was a made for TV movie back in the 70s starring, of all people, Larry Hagman as. Holmes.
There was also the movie They Might Be Giants