i LOVE okami, but i love it despite its shallow and meh gameplay, not because of it.
i love it for it's story, characters, music, graphics and style. i also like "feel" of controlling tiramisu.
but other than that, the game doesn't have much to offer. the dungeon designs are beyond basic and most of them, as you said, play themselves. there's rarely an actual puzzle involved and even the ones that are there have brain-dead solutions.
the world design is nothing special, it looks great, sure, but it's not interesting and doesn't invite exploration.
the challenge is non-existent. i recently finished the switch version, and died zero times during my 45 hours with the game
the combat is basic, the three types of weapons offer no depth, and the upgraded you get in the dojo don't matter a lot. the combat is saved a little bit by the brush technics but unlike their usage in the world, they feel clunky and kill whatever little rhythm there is to the battles.
the brush is probably the only thing saving the gameplay from being completely generic
i think if the game had a less stylized skin and the story/music wasn't as good i would consider it a very mediocre game not worth playing, so it says a lot about how much i love the story/characters/music/vibe of the game that i still love the game despite thinking so low of the actual gameplay.