Really like it. Adds depth to the game and gives everything a purpose (even trash!); and as a bonus, it fits the theme of ACNH.
It's instant access to dozens of furniture and items anytime/anywhere and it creates a sense of community because it's your residents who are teaching you these things and not you mindlessly walking everyday to a shop. It makes the game more open since you're not only relying on bells to get 99% of the items and it pushes you to perform a wide variety of tasks (gardening, growing crops, fishing, chopping wood, hitting rocks, catching leaves, building snowboys, popping balloons, etc) instead of becoming a race to find the best way to farm bells and avoid doing everything else. It seriously pushes the life-sim angle much better than just "lol, let's go shopping".
It was a correct decision to make the second-tier tools buyable at Nook's, as combined with the other QoL of NH, it makes tool breaking almost irrelevant. Everything else is perfect at being not-rebuyable, it would completely diminish the system.
However, it could use a few tweaks. Not bulk crafting, that's totally unneeded, you shouldn't be bulk crafting fish bait and if you're bulk crafting a table or something, then that's the same level of grinding/risk-reward than ordering 5/10 or whatever amount of items per day. If it's absolutely necessary to have bulk crafting, it should be tied to the energy mechanic to make it a risk/reward inconvenience on the AC style. I also don't think all the normal seasonal DIY (spring/mushroom/etc) were bad (if you're just farming balloons for hours just to get more DIY it's your own decision, not the game's fault you want to burnout yourself like that; specially since you can get all DIY from those sets without grinding at all, just normal gameplay).
I do think the 10-day seasonal DIY being exclusive to balloons is a bit too much; so, for those 10-day things, even if Kapp'n is now helping with that, I would have preferred to have another method of getting those DIY, with maybe the last 3 days having a guaranteed Bunny Day-like bottle spawning on the beach with a guaranteed unlearned recipe. This could extend to the normal DIY, they could implement the fairly common idea of a trading/recycling thing where you could swap an absurd amount of DIY for a guaranteed new one (say 20 for 1) to prevent it from becoming the best method and a high-risk high reward swap of 3 for 1 but it could be a dupe. Same for the low-chance floral DIY, those could also be part of the swap. All the others are fine.
Fixing those two things should be more than enough to refresh things and make the system better. The swap could even be with your residents and tied to personalities to keep the community feeling. Maybe you could fix the golden tools being not great by adding an absurd durability or a real-time durability to those, and that would also help in the long run.