I think criticising simple writing is not necessarily without merit, but just saying "the writing is so simplistic it's like a Nancy Drew book" is not enough. I did dislike it initially because of how plain the translation felt, but then the rhythms of the descriptions reeled me in to enable me to finish the book.
I tend to be wary of emotional baiting, and it did feel like I was being baited because the characterisations were so simple - throw in a emotional complication and there you have a story! I dunno. Towards the end the thought came to me, "Is this the cat version of Hachiko?" Be that as it may, Satoru had a far worse (if you can even weigh sorrows of his sort) backstory.

I guess I liked it because the descriptions and the settings really were nice, even if everything felt underdeveloped. It's a calming, non-urgent read.