I’m just gonna respond to a few things in the interest of fairness. I don’t particularly like Tae Kim’s Guide myself, and I frankly never use it. I think I found his explanations too wordy (ironic for someone who writes as much as me), and that it was a little too clear that it was his understanding of Japanese, as opposed to something that might be widely accepted by native speakers, especially specialists. I do think that Imabi is significantly better and more thorough, but I don’t know where the information is from (perhaps because I just don’t use the site enough to know where to look), and so I’m never sure how much to trust the author even though he’s clearly knowledgeable. Finally, I’d just like to make it clear that I prefer to use native specialist sources for understanding how natives see grammar regardless of what language I’m studying (provided I’m proficient enough to read them, of course), so that might make me biased.
This is sad, but given what appears in post #2, I’m very much inclined to believe this is real. His articles feel relatively unresearched anyway.
Actually, it does make sense when you consider that one of the possible motivations for using が is introducing ‘new information’. Also, it’s not wrong that が tends to strongly ‘point’ towards a particular person or thing within a relatively short part of a sentence. Here’s a post in which I summarise the five major differences that I’m referring to, which were apparently compiled by a Japanese grammarian in 1996: Short Grammar Questions (Part 1) - #6135 by Jonapedia
However, I think the bit about ‘subject’ being ‘different’ in English is disingenuous, especially since I believe many of the technical terms used to describe Japanese grammar are words that can and have been translated across many languages. ‘Subject’ is also the English concept that covers the most of what が does in Japanese anyway, so it’s not a good idea to leave it out. Even Japanese dictionaries list ‘expressing/marking the nominative’ i.e. ‘subject case’ as one of its most important functions.
This is actually a common explanation. Tae Kim isn’t the only one who uses it, and I think it’s true to an extent given that が does identify the person or thing responsible for a particular action, among other functions.
I wouldn’t explain it this way, but perhaps I just don’t understand how you draw relevant analogies between ‘the’, ‘a’ and the two particles. I agree that が tends to be used when something is presented for the first time, whereas は isn’t, and perhaps I haven’t quite mastered は vs が, but given that が does have a tendency to point something out very specifically and tie it to an action or quality, I’d say I see it as closer to ‘the’ than ‘a’. However, I know this isn’t your main point, and I agree that ‘answering a silent question’ is a gross oversimplification that’s even less helpful than the (more common) ‘が emphasises what comes before it, and は what comes after it.’ It’s not a very good explanation. Also, yes, constantly using ‘as for’ to explain は is only good for beginners in the earliest stages. It’s extremely unnatural beyond a certain point.
Thing is, when I googled, I couldn’t find any sources explicitly saying it was bad/wrong aside from Imabi and the Chiebukuro Q&A you linked to. Furthermore, there was a very severe lack of explanation as to why it was wrong. Sure, one of the Chiebukuro answers said that there’s a mismatch of formality levels, but I don’t find that particularly convincing since they’re used fairly similarly with practically every other structure expressing obligation. On Google, ‘ないとならない’ is one-third as common as ‘ないといけない’, but it still brings up about 40 million hits. That doesn’t mean all these hits are grammatically correct or that they’re all using it as a structure indicating obligation, but it’s not that rare. Many HiNative answers tackling the difference between various obligation structures also say that they all mean roughly the same thing, with no special correction directed as ないとならない.
I could only find one source in Japanese that provided something which I felt was convincing: a historical usage argument. I think that’s a better explanation since grammatically speaking, there doesn’t seem to be any justification one can provide for why it’s wrong. Here’s the link: 『「なければならない」と「ないといけない」について』. I haven’t read everything, so I might be misrepresenting the author’s position, but it seems the essence is the 〜と as a conditional structure dates from the Muromachi period and is thus relatively recent, whereas ならない dates from the Heian period and is really well anchored in Japanese usage. In essence, there’s resistance to using the two structures together, and it seems it’s because they’re from two completely different eras. That’s why it feels strange.
My point is though… I’m just rather disappointed when sources state something is ungrammatical or wrong without any justifications even when there’s no rule the reader can refer to for easy fact-checking. Imabi may say it ‘doesn’t exist’, and that seems to be the majority position, but no one seems to explain why, and it doesn’t seem all that rare, so I don’t think Tae Kim was entirely unjustified in saying it’s valid. However, should it have been in a guide for beginners? No, I don’t think so. I didn’t even know 〜ないと obligation structures existed until I stumbled upon them. I learnt なければ and なくては first, and they seemed quite sufficient.
This is bad. I agree. No point spamming readers with information that adds no value.
I don’t know… I honestly only hear やる in anime, and it usually has an unpleasant/casual feel, so if this is a guide for beginners, I think it’s justified to tell them not to use it when giving/doing something to/for other people. It’s not ‘normal’ in that sense. However, OK, seeing as you had someone tell you they were confused by this, I see where you’re coming from.
These are the three I’m relatively familiar with, and I agree that they’re much better, at least based on what I’ve seen so far.
All in all, I just wanted to say that I feel Tae Kim isn’t entirely wrong in these examples. I’m pretty sure you’ve raised at least one other example at some other point in another thread which quite frankly shocked me, so I hardly think Tae Kim is perfect, but there’s some truth to what he said. However, these are definitely not the explanations I would have liked to have as a beginner, and I think there are far better explanations of the basics in many other resources. That’s why I rapidly dropped Tae Kim’s Guide as a beginner: I just felt it didn’t suit me, and I wouldn’t recommend it.