There is a number of things written about blood at the moment, but what is the heart of the issue.
It is not doctrine. Religions are able to make up any doctrine they feel like. Most Christians can see that the JW blood doctrine is unscriptural, but individuals will never agree on doctrine.
It is not the lack of logic in the current JW stance even though it is illogical to disallow blood transfusions, but allow blood component transfusions. It is hypocritical to allow blood fraction transfusions but disallow the users of blood fraction transfusion to donate blood.
It is not the history. It is illogical to say a doctrine has come from Jehovah, but to have allowed blood, then not allowed blood or any fractions, to now allowing most blood fractions.
The issue is this. The Watchtower promotes misinformation about the risks of refusing blood. Delibrate withholding of information to lead people to a wrong conclusion is leading to death.
Some of my JW family believe that blood transfusions never saves lives, in fact blood transfusions can kill people. This is because the Watchtower has provided biased information. There are some situations when a blood transfusion is medically proven to be absolutely necessary to keep a person alive. A JW should be given the full story in order to make an informed decision.