It's a game with a number of flaws and problems that show Nintendo's inexperience with creating this massive open-world type of game.
Combat is unrewarding and resulted in me eventually just running past all the random encounters, the vast majority of side quests are uninspired and bland. The world lacks variety and is copy and pasted (Every stable is the same) shrines used to pad out the game. Lack of abilities mean puzzle solving is limited, you basically just get out your magnet and look for something that glows. The map could also see improvement, making it more apparent where you've actually explored.
BOTW is saved by it's polish and soul. I didn't get caught up in any hype so it didn't have anything to live up to for me. It was an 8/10 game for me.
The sequel will eclipse BOTW in every aspect, except sales unfortunately.
Very true. I'm sure the sequel will improve in a lot of ways. Only thing I'd be worried about is going back to the same world - hopefully they change the content and mechanics and everything enough that playing through the same map feels like a new experience. No doubt the sales will be less, but hopefully it'll at least be another 10 million seller and put all pre-BotW Zelda sales to shame. And you never know, since BotW is THE essential Switch experience, maybe BotW 2 will have a Smash/Pokemon level launch.