The bottom line is that Breath of the Wild is the first game in the Zelda series to really elevate it as a franchise since Ocarina of Time. It's the first time since that game that I got that feeling I had when I played the original game on NES, and even Zelda 2 (despite many people hating it, I found it sufficiently different and interesting in many different ways, it was one of the games that got me started on my favourite genre, RPGs), then Link to the Past back in the SNES era, and when I played Ocarina of Time on the N64.
The big problem I had with the franchise is, while games like Link's Awakening and Majora's Mask were interesting for what they were - they didn't really progress the franchise. Legend of Zelda, Link to the Past, and Ocarina of Time all did something to elevate the franchise to the next level. Then the franchise spent nearly two decades wallowing in derivatives until Breath of the Wild. You could say "Well... well... Wind Waker had all that water to sail on" but all that really did was replace Hyrule field as the obstacle course between the dungeons filled with slow puzzles; the games were all basically derivatives of what Ocarina of Time had already done a lot better years earlier.
Breath of the Wild finally broke that cycle of stagnant releases by doing something new and wonderful. it elevated the franchise to the next level they were seeking for nearly 20 years - and it is the most successful game in the franchise critically and commercially.
*For people who are going to press the argument of the meta score of Breath of the Wild being slightly lower than Ocarina of Time - keep in mind that the volume and total percentage of 100%s are substantially higher for Breath of the Wild. Reviews like Jimquisition "I'm giving it a low score because I'm angry at Nintendo" reviews are counted, but shouldn't be if you are looking for an accurate representation. Basically, if you cut off the top and bottom 10% of reviews, you'll get something more reliable - and Breath of the Wild is higher than Ocarina of Time in this case. In statistics, a textbook example is this: in a kitchen if taking the temperature of a room by measuring of 20 objects, and 19 of them are 18-20 degrees, but the oven is 200 degrees, then the average temperature of the room would rise to over 28 degrees with all things accounted for, which would be highly misleading. Cutting off top 10% and bottom 10% would give a much more accurate temperature of the room, and it would end up somewhere around 19 degrees instead of 28 degrees. Basically, if you agree with the outlier reviews, you're not agreeing that the average anyway - rather, you're in the oven, and not where the majority of people would stand.