I think what makes the Nether Update so good is that Mojang really had a clear theme for what they wanted to do. They didn’t just add more content to the nether, they specifically wanted the make the nether a habitable space. As in, you can not just survive, but thrive. So, they added equivalents of wood and stone (removing the need to return to the overworld for simple crafting recipes) as well as more sources of food, and everything else you could need in life.
What I really love, though, is that there was a clear focus on making the nether have all the same sorts of ameneties as the overworld, but all slightly wrong. There’s a bed equivalent, but it’s expensive and needs to be refueled. The wood and stone equivalents I mentioned can only be found in specific areas, making those simple recipes a lot more challenging. There are animals that can be bred and farmed, but they’re also hostile to the player. There are sapient locals to trade with just like the villagers you’re used to, but they attack anyone they don’t like the look of and defend their homes with lethal force.
Instead of the nether being a nightmare landscape that only wants you dead, it now really feels like a bizarre alternate dimension— one where everything you know is flipped on its head and a lot more dangerous, but it’s not totally inhospitable.
