I agree with being able to farm quartz in some way or another. It's the perfect material for farming potential, too. It has very few non-decorative uses, and it's near-impossible to get enough quartz to build anything reasonably big by mining in the Nether.
I do agree with Mastermined that it should spawn in the Nether. Not only does this make sense, and makes sure that quartz is still gated behind Nether travel, but it also gives people a good reason to build a base in the Nether.
Let's not make Minecraft a game focusing around building mob farms, because then it becomes Farmcraft, not Minecraft.
In my opinion, if building the farms requires designing and getting the materials beforehand to build it, it's balanced enough. While you may like building without farms, some people like to think big. Hermitcraft players (Mumbo Jumbo, iskall85, xisumavoid, etc.) and many other players like to build large scale structures, and having to mine hundreds of resources like Iron, Gold or Quartz is a huge barrier between them and building cool stuff. That's why farms are a thing, not just for the sake of amassing hundreds of resources so that you'll never need to go mine for them again.
Do you want to mine for the iron to build a giant spaceship or a huge skyscraper? (Keeping in mind that 7 iron blocks alone require 63 ingots, almost a full stack, so in order to get the 10 or 20 stacks of iron blocks necessary for huge builds, you basically have to be TheMasterCaver.)