Having had some time to sleep on it, I can better clarify the reasons why this would be a bad idea
as we are now speculating. I reserve, of course, the possibility that he was kidding (it would seem contradictory to his blog post), or that what he means by choices and endings doesn't necessarily mean what we're expecting. In the latter case, it'd be much easier for him to "do it right," but I'd have no idea how so I couldn't long speculate on it.
So anyway, reasons why a "standard VN choice node" approach would be bad:
- It isn't really much of an "answer" in any sense. By anyone's standards of what they wanted an "answer" to be, not just the folks who want a whodunnit. The more obviously he makes one answer "right" the less of a problem this is, but even if that is apparently unambiguously clear, I have a feeling alternate explanations, if not obviously wrong, will not go away so gently. And if the "bad" ends are brutal, mean deconstructions of particular theories in order to ensure no alternative exists (as right now, it's very ambiguous unless he starts throwing out scorched-earth facts), I'd find that very childish of him.
- It breaks narrative flow. I've approached Umineko for seven episodes as more of a book than a game. Choices turn it into something I didn't want to read, really; I dislike VNs with choices, generally, and just follow guides because that's a "gameplay" element I really don't enjoy engaging with. Ignoring whether the choice options presented are well-composed, I don't really like the idea of the format breaking up his story.
- This is supposed to be his ending, not mine. Obviously, he's writing all of it, but by putting decision-making in my hand he's basically asserting one of two things. Either he's expecting me to reach an ending I like, or he's got a right answer and he wants to flaunt his own intellect by forcing a reader through a series of choices to "see how you did." It's a poor mystery writer who berates his audience for failing to meet the challenge; tell them it's okay to solve and that they can stop and start reading again to compare, sure, but leave it at that. Nevermind that there are people who don't read mysteries to "play the game." Choices force the reader to "play." I know several people who like Umineko, but don't want to figure out who the killer is. Is that a little lazy? Sure. But it's a valid way to read a detective story, to marvel at the detective's solution that you never even thought about. For somebody who just wants to read to the end, the choices are basically an annoyance. Get a guide or just guess. That's not much fun.
- I worry the choices will be unintuitive even if you have the "right answer." Say the goal is to pinpoint the culprit, and you succeed at that because you figured out the whodunnit. You're then presented with a second choice, one more based on an immediate situation which has never come up before (confrontation with the killer), and which is not really based on having the answer or not. Would it be fair to have a choice node like that? If you got the right killer but picked the wrong secondary choice, did you really "fail" to uncover the truth? Granted, we don't even know what those would be to begin with. Still...
Now, a thought. Battler closes ep7 offering to tell a story. Featherine/Tohya said if you knew the truth, you could write a story. In theory, a series of choice nodes to "tell the story" of the truth could test the reader on what they think they know. But it'd have to be done very subtly to not cause the issues noted above. This would, however, account for "bad" endings; you've told
a story of Rokkenjima, but you didn't tell
the story, because you got some theme or detail wrong. So you need to go back and tell another (kinda
Sands of Time-y).
I have trouble believing any story told with choices that lets you approach the truth of the incident could meet the conditions Battler set forth in the epilogue of ep7, however. Unless that's a hint as to how to make our choices, and even then, it'd probably lack the flair some people seem to be anticipating it would have.