Seems a bit like it'll be what Majora's Mask was to Ocarina of Time. Same core game with some additional systems added on. I'm guessing it'll change less than MM did though. Either way, I'm looking forward to it!
The sidequests are what made Majora's Mask so great though. Collecting the masks was fun, and since each one had a unique ability, with some of them being required to progress other sidequests, each one felt worth it.
Even though Majora's Mask's story was short, that paired with the all-new world made it feel like a brand new game.
Tears of the Kingdom doesn't appear to have a brand new world, and the sidequests in BotW didn't seem worth it for the most part, most of them didn't give you anything unique, you only got a few spirit orbs out of it and some not that useful armor, so I'm not expecting this to be any better there either.
So I don't think it can be compared to Majora's Mask at all. Majora's Mask was everything this isn't. The engine was pretty much the only thing it had in common with OoT.
Too early to say for sure, but there is every indication that this will not be anything like what Majora's Mask was to OoT. It'll just be more of the same, with little significant improvements or changes to speak of.
I was really hyped for BotW, I'm a lot less hyped for this, but I'm sure I'll enjoy it nonetheless. I was really hoping it would fuse the old with the new, and bring back the unique obtainable items you get in dungeons (and sometimes out of dungeons), but seeing Link shield surfing on railroad tracks makes me pretty sure they're not gonna do that.
Although, they could give you a new Sheikah Slate ability in each dungeon, instead of giving you all of them at the beginning. That actually wouldn't be a bad idea, and would be pretty similar to how the unique items in dungeons worked before. And more abilities = more fun. I definitely saw one new ability in that trailer (not sure how it works yet), so I hope there's a bunch more.