Rescinding the blood nonsense would maybe involve them in lawsuits by family members, because of the ones who died until they received New Light ( really a huge deposit in their Bank accounts according to your scenario).
I think the G.B members when first appointed are full on believers, if perhaps ambitious and suffering from the Dunning-Krueger effect, but when they have seen the process that governs Doctrinal changes, then Cognitive Dissonance sets in , with some. Some will remain full on believers.
Whatever, I don't see them making any major changes soon.