BotW is a fantastic game with an amazing world (it's easily the high water mark for open world design in games), but the stuff in it often left a lot to be desired. The sidequests were almost all bad, forgettable, or both, with the exception of creating Tarry town and the dragons (which only led to shrines, which was another problem). Without talking about padding, the problem with the shrines was that most of them just weren't all that interesting. I'd say maybe 20-30% felt like they had interesting puzzles, and even that may be a tad generous. And the fact that they were all identical-looking contextless puzzle boxes made them feel less like interesting content in a narrative sense and a little bit more like Content in a "we've gotta put stuff in this game" sense, which I think explains why it can feel like padding to some.
The Beasts were good, but far too short and infrequent. I'd have rather had fewer shrines and more Beast-like areas, or more areas like Hyrule Castle that were really interesting to explore and had an almost Dark-Souls esque feeling to them in terms of threat and looping back in on itself.
It's a shame. Like I said, it's a great game, but it was deflating to me personally when I realized that everything would lead to a shrine or a Korok seed. The doing of things itself was still good enough to keep me playing the game, which is great! But a little bit more interesting and varied things to do (and rewards) would've gone a long way.