I've seen nothing in React's (or Katana's) architecture that avoids doing things on the main thread when you shouldn't. I'd also argue that GCD offers a nice, elegant approach to not doing things on the main thread when you shouldn't.
But I'd say that MVC-discipline and thread-discipline are baseline skills that I'd expect from competent iOS devs.
RE: dependency management/unit testing, that's an area I agree needs improvement in general for iOS (though I do not see anything in Katana that significantly helps with that). Swinject (as one example) is alright. I'm not hugely impressed.
