My verdict: I liked it, but I didn't love it. Now, whether or not I love something is not usually a function of how good it is (see: Torchwood), and I think there are some thinks that Elementary did very well indeed. Lucy Liu and Johnny Lee Miller are both fine actors who made me like their characters -- though in Liu's case I like Joan for completely different reasons to why I like Watson, and while Miller has some moments that pinged me as quintessentially Holmes-ish, at other times, he was less so. Given that I believe that adaptations should be judged on their own merits, this is not something that I think is a problem -- but it does mean that I'm not going to love it in the way that I love ACD!Holmes and BBC!Sherlock.
In terms of Watson's character, I don't have a problem with the "failed surgeon" thing per se -- in fact, I think it could be really interesting in terms of the ways that professional women respond to failure or perceived failure (I'm suspecting here that she's not fought against any negligence claim because she believes she deserved to lose her job -- but that she may actually be able to fight against it in the future). I'm looking forward to how this is developed. Nonetheless, in the context of Sherlock Holmes, I agree with other commentary that I've read, that it would have been better to retain the "injured military doctor" aspect of Watson's character, and used that to explore issues relating to women in the military and the like. I also miss the sense of Watson as a writer. Again, these things are not criticisms of Lucy Liu's Joan in and of herself; just notes on what might have made the canon feel more Holmes-ish.
I thought that some of the mystery elements were handled better than they are in Sherlock (let us not forget how long it takes Sherlock to latch onto the cab thing in "A Study in Pink"). I liked the rice thing -- that was clever. But one of the things I love about Sherlock is how many little Easter Eggs there are for Sherlockians -- references not only to ACD, but to a variety of filmic, televised, and scholarly reinterpretations of Holmes. I keep on finding new ones, even now! We have a few of these in Elementary (the bees!), but it's not as rich. Which again (I say as my refrain) is not a bad thing in and of itself. It's just not... my thing.
In short, what I think I want is for Lucy Liu's Joan to have her own show, independent of the Holmes mythology. (And I also want to have a Holmes adaptation where both Holmes and Watson are women.)