While the article might be too harsh, I think the general sentiment in the comments are way too lenient.
hanzi is a particular difficult writing system.
hanzi is a particular difficult writing system.
Read for example this classic essay
http://www.pinyin.info/readings/texts/moser.html
written by an actual linguist.
Most children learn their native language(s) properly at about the same age, which suggests that the languages are comparably difficult to learn, and perhaps that if a language takes too long, it'll be simplified. But there's nothing that pushes languages to have the same difficulties.
The main advantage of logographic languages is written information density. If you've ever seen a Chinese or Japanese copy of a Harry Potter book, you'll understand. (They're quite thin.) Also, Twitter is a totally different experience when using hanzi or kanji. The character limit is enough for a paragraph instead of a sentence.
I don’t think anyone claims that spoken Chinese is particularly hard compared to other languages, but that the written form is measurably harder than languages that use an alphabetic orthography.
(I have read claims that Russian is particularly difficult though - can anyone comment?)
In what way? It uses an alphabet just like Latin-based languages, and it's more phonetic than English (but not completely phonetic). I'm sure anyone can learn to write/read Cyrillic in a few days if they already know Latin. The actual language is harder than English because of large number of noun/adjective declensions (depending on plurality, case, gender) which would be a pain to memorize for a non-native. But being an Indo-European language it's still pretty similar to English as far as languages go. Chinese, having a completely different writing system, completely different sentence structure, completely different fixed expressions, completely different sounds (and tones!) is orders of magnitude harder.
My wife knows Russian and 5-6 other languages on a tourist level or better. She says Russian has both a difficult and a simple aspect: Newspapers use a large vocabulary so reading with moderate education is tricky, but people's accents are easier to deal with.
Moreover I find your last sentence to contradict the previous. I don't know what you are trying to say, but you are talking about a different domain.
I know there have been attempts to each people purely spoken language and purely written, but those are rare. In practice the two seem strongly connected.