I am opposed to empathy as a moral tool. Empathy has all sorts of known biases - we feel more empathy for people like us, attractive people, etc. In the west, for example, we have less empathy for black people:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3108582/
http://www.plosone.org/article/info:doi/10.1371/journal.pone...
Furthermore, even in the absence of easily predicted biases, emotional reactions are simply nondeterministic. There is no reason to believe they will converge to anything useful.
In contrast, principle-based morality doesn't have this flaw. If you take a principled position that poking people with a needle is bad (to borrow the example of the first paper), then it doesn't matter if you are poking a black or white person - the abstract principle of "don't poke people with a needle" is sufficient.
I realize this idea certainly bothers people who take personal pride in feeling empathy, who make it part of their identity. That doesn't mean I believe it to be wrong.