[zorahk]

Your logic is faulty on multiple levels, but basically the spoken language has nothing to do with the written language. Japanese could not write before Chinese was imported into Japan, and yet the Japanese language existed beforehand.

Your suggestion for a new writing system based on mora and pitch accent, while on paper a good idea, is in practice a terrible idea. Most speakers of Japanese have no idea what pitch accent is. It's one of those phrases probably invented by some foreigner studying Japanese. You're under the mistaken assumption that we know what the pitch accent for a particular word is. If I saw hashi or something that I know it would be different from hashi. That's not the case. We do not know the word from the pitch accent. We know the pitch accent from the word. The rest is mostly gleaned from context. Pitch accent differs from dialect to dialect so attempting to standardize it is impossible anyway. Proper pitch accent is, literally, something that only exists on TV (EG: NHK). It doesn't exist in real life.

The example of korean is nice, but korean is not Japanese. Also, there are some studies which if you take the time to read show that reading mixed script (hanja + hangul) is actually faster than hangul only script.

Your entire point is pretty much invalidated by the fact that you apparently don't understand Kanji very well as you said in the last paragraph.

Basically, the only people who advocate the removal of kanji from Japanese are whiny foreigners who complain that its too hard to learn. It's not designed for you, I'm afraid.

Originally Posted by OBrasilo

I don't get it why most Japanese speakers maintain Japanese is incomprehensible unless written in Kanji. In my opinion, that's false because were it true, spoken Japanese would have pretty much died a long time ago already, as it would mean spoken Japanese is impossible to understand. Yet people in Japan still to this date speak Japanese in their day to day life.
Obviously the spoken language has a way to distinguish between (quasi-)homophones. It's pitch accent. So make a writing system for Japanese that notates not only the basic morae (not syllables, contrary to popular belief) that kana notate, but also also the pitch accent, and add spaces to it, and you have a good writing system for Japanese that doesn't require thousands of characters to be read properly.
Phonetic simplicity doesn't require thousands of characters to be written properly. Case in point, Hawaiian language, which arguably has even less sounds than Japanese, yet it's perfectly understandable when written in the alphabetic Latin script.

As for people claiming that any writing system apart from the current one would make Japanese somehow un-Japanese... once again false. Do people even realize that the kanji were taken from Chinese? They're even called, literally han characters which means Chinese characters. Not that the Latin script was invented for English, not at all, just the same, it was invented for Latin, from the Greek script.
A writing system shouldn't be a founding pillar of one's culture or language. Look at Romanian. It used to be written in an extremely odd variant of Cyrillic, with lots of unique characters, then one day it was changed to Latin script, but do you think the Romanian culture and laguage became any less Romanian becuase of that? No, not at all.
Just like Korean didn't become any less Korean when it switched from hanja (the Korean equivalent of kanji) to their own phonetic-cluster hangeul writing system.

My question is, why don't the Japanese for once look at Korea and see how the Korean language was able to drop hanja and develop its own hangeul, and do something similar in Japanese as well? After all, the switch from hanja to hangeul increased literacy in Korea a lot, so it'd be just logical to assume that a switch from kanji+kana to a new, easier writing system would increase literacy in Japan as well.
And if the new system spaces the words and notates things like pitch accent, and other things that disambiguate words in spoken Japanese, then understandability wouldn't be a problem at all.

Edit: And yes I have tried to read kana-only Japanese text, and it's pretty much easier for me to parse only kana, than it is to figure out which kanji in a group of 5 or so kanji belong to one word, and which belong to the next word.
And I have tried to read hangeul-only Korean text (pretty much standard in Korean today), and again, it was pretty easy to read and understand it. And the little knowledge I have of Mandarin Chinese enables me to understand some sentences written in Pinyin pretty fine as well. Not something I would say for the native hanzi, though.