1. That Chinese writing is inherently inefficient. It's actually very efficient...to read. And nothing beats the efficiency of having a script that maps perfectly to the language. Also as sibling comment notes, UTF-8 is a thing.
2. That there is no relation between written characters and phonetics. Incorrect, as several sibling comments point out.
3. That Japanese kana represents a successful "modernization" of kanji that Chinese should emulate.
4. That Chinese is "basically kanji" - assuming the Chinese and Japanese languages are essentially interchangeable. They...are not. I can't even begin to emphasize how much they are not. Chinese is subject-verb-object while Japanese is subject-object-verb, for instance. Chinese also has many phonemes that are incompatible with Japanese, which would not be covered in hiragana. Finally, kanji came from Chinese and has subtle differences and while it is mostly a subset of Chinese hanz, it has its own slightly different character set
GP is making understandable misunderstanding due to how the three Far East countries are presented in the world at large, that there are three countries in Asia that practically touches each others, just like Germany is with Belgium and Netherlands in Europe.
Tokyo from Beijing(2000km/1200mi) is about as far out as Paris to Kyiv. Far East countries are also separated by seas, like Mediterranean countries across the sea. I doubt a lot of Parisians have meaningful ideas of "basically Latin" Ukrainian any way or form, or Italians with Tunisian, but there's such false instinct that forms out of above-mentioned presentation that those Asians are rather next door neighbors.
That and mistaking personal difficulties and inefficiencies associated with understanding languages in non-native manners as inferiority of the foreign one.
It’s really bizarre to see someone claim kana has anything to do with “modernization”. The Japanese modernization and industrialization period is famously associated with translating Western concepts and terminologies into Sinitic words that later spread to China, Korea and Vietnam.
That was true like 100 years ago, but nowadays katakana words are extremely popular and increasingly used over their Sinitic counterparts, so I feel it's a valid argument.
Also it's not uncommon for words like ろ過（濾過）to be written in part kanji especially in news... if that trend continues beyond the 常用 kanji we might end up with a Japanese that is closer to Korean.
The modernization argument only makes sense if your society is economically or militarily inferior to the society you want to emulate. It was the case 100 years ago, but not today.
The Japanese economy has been stagnant for over 30 years with no end in sight. Following the same logic, Japan should perhaps “modernize” their language by following China, which is a ridiculous conclusion as you can tell.
1. That Chinese writing is inherently inefficient. It's actually very efficient...to read. And nothing beats the efficiency of having a script that maps perfectly to the language. Also as sibling comment notes, UTF-8 is a thing.
2. That there is no relation between written characters and phonetics. Incorrect, as several sibling comments point out.
3. That Japanese kana represents a successful "modernization" of kanji that Chinese should emulate.
4. That Chinese is "basically kanji" - assuming the Chinese and Japanese languages are essentially interchangeable. They...are not. I can't even begin to emphasize how much they are not. Chinese is subject-verb-object while Japanese is subject-object-verb, for instance. Chinese also has many phonemes that are incompatible with Japanese, which would not be covered in hiragana. Finally, kanji came from Chinese and has subtle differences and while it is mostly a subset of Chinese hanz, it has its own slightly different character set