[unscaled]

I never had the pleasure of taking them myself, butI'm pretty sure Japanese grammar classes are not so fun as you imagine.

Putting aside that the norm in Japanese school is rote memorization and pedantic attention to details (e.g. you'd memorize dates of historical events), the Japanese grammar that is taught in class is traditional Japanese grammar. It's pretty streamlined compared to the abomination that is medieval Latin grammar (which remains the basis for English grammar taught in class), but it still targets Classical Japanese and uses rather obscure terms where clear diagrams would suffice.

I'll have to ask, but I think that instead of diagrams, Japanese students mainly need to memorize the difference between Izenkei, Mizenkei, Renyoukei, Rentaikei and Shuushikei, even though the last one is irrelevant for modern Japanese.

And of course Japanese wasn't "designed" any more than English was. There are dialects with widely varying grammar and vocabulary, and there some aspects which are very hard to learn even if you ignore the writing system (e.g. the proper use of Wa vs Ga, the proper use of emphatic sentence endings like no/n'da or yo). Inflection is way more regular than English, and syntax is pretty streamlined, which is a boon.

[iamnotlarry]

Wa/Ga aren't that hard. Mostly just subject vs topic. Just like objective and subjective isn't that hard in English. Of course, most Americans can't master objective/subjective.

The trick for wa/ga is often just to remember that subjects are often implied in Japanese and missing from the actual text/speech. So, "Nekko ga suki desu" because the "watakushi wa" was implied.