Here are the reasons why I don't think a change can be dismissed --
Watchtower legal is very influential when it comes to making changes. The blood issue remains a huge legal liability not just in terms of lawsuits but also in allowing the religion to operate legally in different countries. Serious legal or political pressure can make changes.
The blood doctrine has been continually watered down since its inception without serious "blow-back". For instance, hemophiliacs were originally not allowed accept Factor IX, a decision that was later reversed. It is likely that some died in the interim - yet apart from "apostate" sources there hasn't even been a blip on the congregational level. The same could be said for other treatments, therapies, and components.
The Organization routinely changes doctrine and practice and most importantly Jehovah's Witnesses are conditioned to accept these changes without question. In recent times the Org doesn't even attempt to make serious justification for new teachings - more or less just putting it out there. Any who would have grievances with the Society would be summarily disfellowshipped. This has been a successful tool in silencing dissent.
There are ways to make taking blood a matter of conscience without coming out with an article with big red flashing lights saying "ATTENTION: FLIP FLOP NEW LIGHT HERE - YOU CAN TAKE BLOOD!!!" Sometimes simply not enforcing the rule gives de facto permission. Oral sex is still condemned on the books but it is regularly practiced by Witnesses and might as well be a conscience matter as time goes on. The Society could simply state that matters involving blood and medical care are complicated and that they are no position to give advice on every new procedure, treatment, and use of a component. They could say that such decisions are best left to the Witness and his caregiver. They would uphold Acts 15 and say that it should continue to act as a guideline to be followed by Christians. They could tell publishers not to be concerned what others choose as it is a private matter and caution others to keep their medical decisions private. If publishers have questions they could direct them to speak with the elders. The elders would be instructed to take no action against those who take blood transfusions. (This is already in place to a certaine extent as one who takes a transfusion is disassociated by actions and not directly disfellowshipped.) Steps like these would effectively give medical liberty without rocking the boat too much.