Yeah, the ability to climb just about anything is a big one. I think another element that makes the game so successful is Hyrule's clear readability. A lot of open-world games knock you over the head with foliage/structure density, and thus your view, particularly at ground level, is obstructed. Here, you can see for miles, and landmarks/points of interest stand out better as a result. It's almost as if the limited technology allowed for this by accident. I feel like the team must have embraced this, but maybe that assumption is a stretch. What comes across as simplicity or inferior technology results in a world that is easier and more fun to explore.