This has been a controversial issue among doctors and medical ethicists. I think it basically comes down to the fact that physicians have a responsibility to establish the presence of informed consent. Is it really possible for a person to give informed consent if they are not accurately informed?
The Watchtower has made some improvements in this area, but still have a long ways to go in my opinion. A good place to start would be by publishing accurate statistics on the effect of anemia in JW populations, and acknowledging the well known limitations of "no blood" alternatives. Particularly in cases of child birth complications, blood disorders like leukemia, and trauma.
Here is what one prominent medical ethicist has suggested for fellow physicians. What do you think? Does it go far enough or too far?