Thanks, MacHislopp. As I suspected, the really big notion they have not changed:
Hence, we do not donate blood, nor do we store for transfusion our blood that should be ‘poured out.’
So they have NOT changed their position on one storing his/her own blood weeks before surgery. I couldn't imagine them changing that one, at least at this time. Too many have died from not doing it, and changing it now would open the Pandora's box that they are so afraid of.
As others have stated before, they really are like rabbis writing the immensely detailed Talmud. The difference, of course, is that it was OK for ancient and medieval Jews to disagree with the rabbis and they could stay in their congregations. It took a lot more to get expelled.
What changed about the transfiguration vision?
What did they change about early Christians' observance of the Mosaic Law?
Are they now accepting tribal marriages?