To be honest that’s also not exactly how I picture Japanese anymore, but I do remember feeling like this at some point during my learning process.

I think it’s partially because of the way in which Japanese is taught at large. You learn that Japanese follows a very rigid [word+particle] structure and these are your building blocks. Which while not completely untrue, obviously doesn’t exactly represent the way the language operates in the wild either.

Nowadays I’m far more likely to see the patchy and very chaotic nature behind Japanese. How okurigana uses are inconsistent a lot of the time, or how you can see the places where Classical Chinese was retrofit to very awkward grammar for it, or how historical changes in pronunciation has led to weird spellings or even entire conjugations.

But I guess that comes with getting more intimate with the language and knowing how to shape it to your own needs. I can see how a first approximation to Japanese language makes it appear blocky and structured. That’s kind of why you start with many of those forms in the first place.