A purse by another name?
We have a suitcase that expands using a zipper, so the concept is out there. I'd like to see what it looks like after he's used it actively for several months. I suspect he won't use the expanding feature of the small pockets that much, or else will find one or the other of them rarely gets "shrunk" because humans tend to be creatures of habit.
Personally, I also feel that with much weight added to the bag, that for me at least, I would need wider shoulder straps.
I also couldn't help but notice the similarity of his pack with the Japanese Elementary School Pack:
The article I took the picture from talks about how this design is good for posture and that the pack is of a quality that will last through 6 years of school use. Considering that when my children attended elementary school, most students wore out a pack every year because most of the packs were cheaply made, quality leather seems like a good investment.
https://press.ikidane-nippon.com/en/a00093/
Even though Skill Tree admits that he's just learning, he may well have managed that level of quality.