Hmm. I'm aiming to learn around 4000 words before I start working on writing kanji. Another

it may not seem as bad if you remove the writing systems and use only romanji

Sure. And I still think it's a 3 if not 4 out of 5 on the difficulty scale for your typical westerner who speaks a germanic or romance language natively. Pronunciation is easy, so you could memorize sentences and whatnot and fumble through a vacation somewhat well, but actually being conversational and sounding more-or-less like a native (grammatically speaking) is an entirely different beast.

Grammar is simple on the surface: subject + "wa" + direct object + "oh" + verb conjugation. However, the subject and direct object can be dropped, prepositions go after the noun, and there are a lot of subtle differences in how ideas are communicated (I'm not strong in Japanese, but in Korean, your farewell greeting depends on who is leaving). So not only is everything flipped around from how a westerner expects things, but there are also a ton of small differences in how ideas are conveyed that make it a lot harder to become fluent vs another western language where structure and ideas tend to be a lot more similar. And that's not even getting into familiar roots.

i find Spanish to be quite difficult

Really? It's usually one of the easiest languages for a native English speaker to learn because it doesn't have any new sounds and there are a ton of shared roots (saying English words in a "spanish" way is surprisingly likely to yield a valid word: e.g. respect -> respeto).

Oddly enough, I have a hispanic coworker who learned Japanese (super into manga and anime) and they claim it was pretty easy, and then complain about stupid English-isms. So yeah, idk, maybe language difficulty is super individual.

especially when there is no rule for how the genders are assigned

Maybe that's why you struggled w/ spanish?

For me, memorizing nouns isn't hard, and if I have to learn gender, I just memorize the noun w/ the gender (der tisch, die mauer, das auto). It's been many years so I've forgotten a lot, but I just memorized vocab by saying the gendered article with it, then it kind of became second nature.

I do the same for Spanish (el eroplano, la escuela). Spanish is even easier because the endings usually give it away.

German is certainly difficult though, but less because of the genders (for me), and more because of the tricky grammar. There are a ton of rules, and while they're consistent (i.e. no laundry list of exceptions like English), there's still a ton of them.

If you remove those written forms, it’s only a level 2 language

Do you have a source for this?

Also, it's almost impossible to ignore written forms. If you're going to get around in Japan at all, you need to at least learn hiragana and katakana (not hard, maybe a month to learn?), and probably a few hundred kanji. But learning Japanese has been about as difficult as learning Korean for me, and I learned both after learning Tagalog, so I was already prepared for learning languages with very different structure (Tagalog does VSO with funky verb conjugations that change what subject and object mean, but it's marked like Japanese and Korean are).

And Korean is simpler in many ways:

• writing system is very blocky and uses spaces between words, which makes it easy to learn - no asterisk needed when determining the difficulty level
• Korean numbers aren't conjugated w/ the counting word (I can still understand if I'm not familiar with the counting word)

Same in some:

• honorifics are similar; Korean technically has 7 levels, but it seems most people just use three (informal, polite, higher status) unless they need to talk to the President or something
• two number systems (native and "Chinese") and counting numbers

And worse in some:

• relationship terms - they're different depending on your gender and which side of the family it's on (e.g. my MIL has a different term than my SO's MIL [my mom])
• pronunciation - several sounds just don't exist in English, and that's really hard to develop
• morphology - Korean will combine sounds depending on what comes before (e.g. "un" marks the subject like "wa" does, but if the previous word ends in a vowel, it becomes "nun"; when two consonants are together, one is elided; etc)

I would say Korean is a little harder than Japanese w/o writing, but Japanese becomes harder when you include the writing system. That's why I say it's at best a 3 and probably a 4, and Korean is solidly a 4, if we're doing a 1-4 scale.

hiragana and katakana are actually somewhat easy to learn, so I’m not sure why you bring those up and not kanji

Yeah, they're not that hard, but I found hiragana pretty difficult because the swoop-y lines kind of blended together and made it hard for me to remember which is which. But once you are confident with both, you can look up pretty much anything you need in a dictionary, since most dictionaries and many things like menus will have hiragana or katakana renditions of any kanji you run across. Romanji pretty much only exists for foreigners until they're comfortable w/ hiragana and katakana.

Kanji is a whole beast unto itself, hence why I didn't bring it up. You can try to learn radicals, but that only gets you so far, and my experience is that it's easier to just memorize the kanji than try to break them down. I hear radicals work a lot better in simplified Chinese, they just fall apart more w/ kanji.

And yeah, you need thousands of kanji to be "literate," but only a few hundred to get by (i.e. "conversational" written Japanese). You'll run into a bunch you don't know, but you can probably figure it out from context.

Any language will be easier if you absorb its content, but that doesn’t have any bearing on the difficulty of it.

My point has nothing to do with culture and more to do with hearing common words frequently in context. If you can immerse yourself in the language, you get a feel for how things fit together, which can turn things like conjugation from rote memorization to being somewhat intuitive, because you've subconsciously already figured out some of the patterns.

If you watched a ton of anime in Japanese while reading in your native language, you're already conditioning yourself to learn Japanese better because you've already started understanding patterns subconsciously.