I've "learned" Objective-C, but I would not call it easy. Moreover, it's not just the language, but the entire toolchain: neither XCode nor Cocoa are intuitive

I've "learned" Objective-C, but I would not call it easy. Moreover, it's not just the language, but the entire toolchain: neither XCode nor Cocoa are intuitive to new developers, whether they have experience in other platforms or not. IMHO, it fails the first half of "easy things should be easy, hard things should be possible". Personally, I've gone the HTML5 route, both to leverage what I already know, and to maximize compatibility with as many platforms as possible. Though I can't do everything Cocoa can do, I can still do quite a lot, while still paying deep attention to the little touches of user experience. I don't blame Flash/Flex devs for wanting to do the same with their existing skills; time will tell how those toolsets fare in practice regarding UX and performance.