Here is my exact experience with BOTW so TOTK fix all these
have mixed feelings.
On the one hand, Breath of the Wild is the first Zelda game in a long time that actually attempts to be challenging. From Wind Waker onwards, the games were explicitly designed to be very easy, with deaths occurring only a handful of times (if you're at all experienced with games). BotW at least deserves credit for its intent.
However, that attempted difficulty is undermined by the sheer brokenness of its mechanics. Food, armor, and flurry rush all trivialize the combat to an obscene degree once you understand them. I think the fact that Zelda had been easy for such a long time meant the Zelda team didn't quite understand how to design a consistently challenging game. That's not to say that the game getting easier over time is entirely unintentional (like with the champion powers), but the sheer imbalance of truffles, for example, makes for a very sharp difficulty drop.
Another issue is the lack of enemy variety, as you alluded to. It's hard to stay excited about the combat when you're facing the same enemies over and over, just in different colors. Your first lynel fight is arguably the peak of the combat system, and that can happen a few hours in. There's not enough novelty to sustain the game's length.
A third issue is how durability works. There's been a lot of talk about durability, and there are moments in the game where it shines, but it undermines any sense of weapon progression. Every weapon in the game (except the Master Sword, which itself is limited) is ephemeral, so you never feel objectively more powerful.
The last big issue I have is the controls. In my opinion 3D Zelda has always controlled very stiffly. Ocarina of Time was still figuring out 3D combat so it can be excused, but its sequels copied its movement too faithfully while ignoring all the innovations that happened in action games since then. Breath of the Wild is a bit smoother, but you can still feel that vestigal stiffness. Compared to something like Nioh which released around the same time, it's night and day. BotW isn't -just- an action game so it's not an entirely fair comparison, but it feels like a relic compared to its contemporaries.