Levelling?
Alchemy?
World physics?
Combat? (Or indeed, lack of)
Monster A.I?
Let's not forget that the Witcher 3 also ran like shit on release and still to this day only runs well on a monster PC or a pro/x boosting it.
Leveling was fine for me, I had enough fun leveling and running around in the world and learned about the map as I went through it.
Alchemy was fine for me, but I'm sure there are ways to "break the game" through alchemy, just as you can break other games through specific builds.
World physics were fine for me, really don't get your issues here, maybe you had a faulty console or pc?
Combat was fine for me, I had just come off dark souls and didn't mind the change of pace. I can play Fire Emblem and have fun and move to Zelda and have fun and move towards the next from softwares game and have fun with that. Rarely will there be a combat system that truly feels a hundred percent fun for me, and when it does it's usually due to a gimmick i genuinely enjoy - like leveling additions on the legend of dragoon. Others will find it dogshit, I'll find it fun.
Monster A.I was A.I like in any other game, in other words fine for me.
Item balancing was a big issue as supposed "epic finds" were throwaway items not worth keeping.
For me there was the added literal headache from witcher senses, but i won't hold that against the game.
Played it on the first-gen ps4 and had no run-issues. I recently got Tomb Raider as a gift from a friend on the pc, and it keeps crashing constantly due to terrible programming. It's a beautiful game with interesting game-play, but those issues wouldn't annoy me if i got it on the ps4, I'm sure, so while I wouldn't recommend to people to play the pc-port, i'd happily say the game itself comes across as fun and enjoyable.
BotW:
Recipes - Link can't keep a cook-book.
World physics - Horses are scared of going down a slightly downward angle and you have to force them to do a weird as feck dance to get down.
Monster A.I is simplistic as feck in BotW just as it is in most other open world games, not holding it against it, but it's not pushing stuff here either, and I wouldn't expect it to.
And this is from just a few hours of playing the game.
Obviously I think BotW is a fun game so far, but it's not the masterpiece a lot of people claim it to be - for me. If it is for them, that's great! My best friend has put in 500 or so hours into BotW and is loving it, finished it fully on both the wii u and the switch. I won't tell her that the game is shit as it's obviously one of her favorite games of all time, but we can agree that there is a difference in how enjoyable it is for us as individuals and it has it's massive upsides and it's downfalls like any other great game.
I don't believe I'll see a perfect game anytime soon, but most are enjoyable as they are.