As far as the major events, I think you have to accept those books. I can see writing the trilogy off for the purposes of characterization and so forth, and I really do think the relative disinterest in WoT discussions and theories, following ToM, when Sanderson's narrative flaws really began shining through, in the homestretch of the series, a point when they should have been at their peak, can be attributed to his poor writing, and mishandling of the story. That said, however, the events have to be considered canon. Rand beat the Dark One the way aMoL says he did. The people who died, died and so forth. We might have been happier about some of the more troublesome events of that trilogy had we been able to read Jordan's description or character-rationalizations of their actions, but the things that happened, happened. Maybe we can write off the characterization as a world-wide Gas Leak, but we're stuck with B-Sand's contribution.

To the extent I agree with the idea, I might, for example, refrain from citing Egwene's more atrocious actions in the latter books as proof of her detestability, but that's about as far as I'd go. I certainly would not accept a counter-argument that if RJ had written the books, she'd have behaved a lot better.