Aaaaaand I lost everything I wrote. Rewriting the same crap twice is my hobby. It's like eating shattered glass, or listening to my sister's favourite song, it's wonderful.
To my knowledge, ZUN was very, very drunk when he wrote the plot to Imperishable Night, so my guess is that ever since then, he's been trying to write himself out of the holes that he created from that inebriated stupor of his...
Having read Silent Sinner in Blue, however, I can safely say that I don't care much about it, though, since the Watatsuki sisters, who consist of a literal walking deus ex machina and a haughty cur, happen to be the only two characters in the entire Touhou universe that I absolutely despise, with the only redeemable aspect about them, in my mind, is that I happen to like their character designs. With that being said, I can safely say that I hope that ZUN doesn't decide to ever venture back to the Moon any time soon, since that inevitably means that we will be running into them again~ :wat:
To answer B2WL's claims about ZUN being drunk while writing his games, I'm just going to put on my fake beard, my fawkes mask, and I'll pretend being awesome and know more than him about ZUN. Except I won't, so let's not.
While ZUN is probably drunk when he's writing the dialogues, I for one happen to think that, maybe, there's a slight possibility that he might not be drunk while looking for materials. Wild and Horny Hermit has some interesting stuff about nuclear fusion, and SSiB is filled with references to the moon, scientifically and religiously speaking, and you can't be a scientist when you're drunk. You can be a philosopher, but not a scientist. Trust me, I tried. I managed to prove that a buttered cat doesn't fly. I also managed to prove that same cat hated butter. And I proved that cats are elastic enough to scratch your face even throught you're throwing them through the window. Next time I'm drunk, I'll try to stretch one, just to prove my point.
Anyway, about ZUN and beer, I'm willing to bet that he has a basic idea of what he was doing when he wrote SSiB's script, so you can't ignore it because "he wus compelety drunk". And about beer, well, it's delicious when NOT mixed with coca. Trust me, I tried that too.
And about 2BWL's claim of disliking the Watatsukis, well, there's nothing I can do about that, except recommanding electroshock therapy. And also, let it be known that if someone wants to jump in this thread to say something stupid like "I was passing by, I saw a light, thought I'd come and say I hate them too, kthxbye", I'm still looking for brains, to make a pie. A delicious pie. With cheese. Mmm, cheese. Everyone like cheese. The moon is like a giant cheese hanging in the sky.
Personally, I loved what ZUN did with Imperishable Night. The story on which it's based - the Bamboo Cutter's Daughter - is a classic and all, but the ending is really unsatisfying. There's no real reason given for why a baby appeared in a stalk of bamboo in the first place, and when the Lunarians come to fetch her, she's just "lol bye every1" and that's it.
In Imperishable Night, however, we have a classic element of the "forbidden fruit" which leads to Kaguya's exile. When all is forgiven and Lunarians come to fetch her, Kaguya displays real human emotion (unlike the other fictional character on which she's based), by expressing attachment to her human world. As does Eirin, for the matter, who feels guilty for her part in all this, and decides to help her friend.
To my mind, IN makes a lot more sense than the myth from which it's derived.
Seriously?! I like IN too! Let's make a fanclub! Wait- Actually, nevermind.
And well, yes, Imperistamble Nacht makes more sense than the real legend (I'm willing to bet that the original legend was in fact a story about how immortality sucks and how you should be happy to be a lowly pleb working for your overlord and being whipped on a daily basis), but it's still hard to take it seriously, as the morale of the story is hidden under THOUSANDS AND THOUSANDS OF BULLETS and a horseshitload of humiliating and fiery deaths.
But something is pestering me about your post, namely, Kaguya's "real human emotion unlike the other fictional character on which she's based". As far as I remember, in other words, not much, given that I reinstalled Oblivion and became Sheggorath while laughing manically in front of my screen, the original Kaguya displayed some regret too when she was forced to leave the Earth, and it's why she gave them immortality elixirs.