I am not sure if Chinese and Japanese can be equated like that. I find Chinese much easier to learn than Japanese because Chinese characters have plenty of built-in pronunciation mnemonics that don't help as much with the Japanese pronunciation. When I studied Japanese, I wasted lots of time coming up with stories to remember complex characters.
Maybe it also depends on whether you have good pictorial memory or need some kind of analytical system, I definitely belong to the latter camp.
You're right, I think the consensus is that the Japanese system is much harder than the Chinese (i.e. Mandarin). The reasons are:
1. it consists os three different systems side by side with complex and sometimes arbitrary rules of switching between:
2. Japanese and Chinese are totally unrelated languages, so the Chinese characters were bolted on due to cultural reasons (similar to how Turkish was written with the Arabic alphabet previously). Chinese characters evolved naturally and are suited with Chinese, since many words were single syllable. They are ill-suited for writing languages unrelated to Chinese.
3. Finally, Japanese has a complicated honorifics system which is hard for foreigners to grasp.
The super complicated Japanese writing system is to be contrasted with the Korean system, which although it uses many Chinese characters (again die to cultural reasons) has a system that is ideally suited to its phonology. I think the difficulty of learning spoken Japanese and Korean would be on par; the writing system makes learning Japanese really hard.
