The primary question facing SAD-ism is a microcosm of the bigger dilemma faced by Christianity and the broader problem of all organized religions.
Specifically, did EGW or whoever wrote Hebrews have the authority to speak for Jesus and more generally, can any human-including Jesus-speak for god?
Reasonably, an almighty god by definition must have the power to communicate directly with any of his creatures and as far as I’m concerned, if there is any good news in the NT, it is that, I.e., god is always with us.
So logically it seems prudent to be skeptical of anyone who claims that god miraculously gave him or her a message that our creator didn’t-or for some reason-couldn’t have delivered to everyone personally.
For my part, I’m particularly suspicious of those who claim to speak for people who can neither confirm or refute the content of their “massages from on high” due to the fact that the message purportedly came from a dead person.
(And, yes, I’m looking at evangelists like EGW, Paul and whomever else claims to be god’s gift to humanity or anyone who insists that their words must be accepted on faith as they cannot immediately be verified by reasonable thought and direct experience.)