You're right in that my site is for people who've already mastered kana and some basic kanji, and there are already so many resources where you can learn those, but there are relatively few for intermediate and advanced students, and that's what I'm addressing.
As for learning kanji by writing by hand, that's actually my own m.o. when dealing with an assignment (i.e., I write all the words out longhand before looking up those I don't know).
But digital input methods have become so much of a crutch, that many native Japanese (especially the younger generations) cannot write by hand any more b/c they forget how.
It's an exaggeration (a huge one) to say that many native Japanese cannot write by hand anymore due to technology. Rather, they have forgotten the stroke order on certain characters, or often confuse two similar characters. It's very debatable as to whether this has been caused by more widespread use of computers, or if such "character amnesia" has always been present. The same can be said for spelling: Do you think English speakers never made spelling mistakes before spellcheck?
> It's an exaggeration (a huge one) to say that many native Japanese cannot write by hand anymore due to technology
Sure, such an absolute statement is an exaggeration, and yeah, it's "debatable," but Japanese themselves seem pretty firmly convinced it's the case.
Practice is necessary to maintain a complex detail-oriented skill, and when many people are doing most of their major writing using keyboards of various sorts, and only writing by hand in very casual and formulaic contexts, there's going to be some fallout.
I think this is rather different from spelling mistakes because spelling mistakes occur regardless of the input method used (computer text entry of western languages is much more "literal" than computer text entry in Japanese). If you write in English at all, regardless of input method, you're going to exercise your spelling ability (even if using a computer lets you spell check, there's still a feedback loop). Japanese text entry using a computer, on the other hand, is completely different than writing by hand; they exercise very different abilities.
No, Japanese people do not seem pretty firmly convinced "that many native Japanese (especially the younger generations) cannot write by hand any more b/c they forget how".
This problem is often reported on the news in Japan, and the problem is that people are forgetting things such as: 1) the correct stroke order for difficult kanji 2) the exact radicals in rarely used complex kanji. For example, 薄 and 簿 look similar, but the top radical is different. Confusing these rarely results in someone being unable to understand the desired meaning, but will elicit eye-rolling and chuckles.
It's absolutely not the case that Japanese people can't write by hand anymore.
A better analogy would be cursive writing. Most young Americans can no longer write in cursive. Their handwriting has become simple, inelegant, and they probably don't follow the "correct" way of writing their letters. But they can still write. Just as Japanese can still write.
Perhaps I could have been more clear. I'm not defending your absolute statement. As I said it's clearly an exaggeration, but it's so absolute that it's at best a strawman—I don't think you'll find many people trying to defend it, so arguing against it is kind of pointless...
However, many Japanese people are indeed firmly convinced that Japanese—and particularly young Japanese—have non-trivial problems writing by hand, and that it's because of computer usage. I know this because I hear them say it constantly...
As for learning kanji by writing by hand, that's actually my own m.o. when dealing with an assignment (i.e., I write all the words out longhand before looking up those I don't know).
But digital input methods have become so much of a crutch, that many native Japanese (especially the younger generations) cannot write by hand any more b/c they forget how.
It's called "character amnesia": http://en.wikipedia.org/wiki/Character_amnesia