I have not looked at Swift at all. Or Objective C. I have done some work in C#. The biggest problem I have with these "next big thing" languages and the reason I won't even bother looking at them now is they don't seem to end up being ubiquitous. Swift/Objective-C in reality never seems to be used for anything but Apple platforms, because Apple is pushing it, and nobody else really. C# is used for Microsoft platforms, because Microsoft pushes it, and nobody else really. With their vested interests nobody then seems to be able to agree on a common language going forward that would be available to develop on for any device.
For the dozens of devices I've programmed for over the years, one thing I could count on is C being supported. Likewise, C++ for any platform actively supported in the last 15 years. I wouldn't want to code an app in C# for an MS platform then rewrite it in Swift for an Apple platform, then C++ for some other platform. Why not just use C++ from the start to save the porting headaches/cost? I guess I've lived in an extremely cross-platform development world for decades so to use anything else would feel idiotic. So at this point I have a feeling I'll be coding in pretty much nothing but C/C++ until I'm dead.
Java seems to have been the biggest attempt to get a "modern" language/development available in all sorts of places. But the language is too high level, and there's the whole run-time thing. I don't think I'll be using Java on an SPU any time soon. Which is a big problem I have with all these new languages, they tend to go too high level and leave the low level stuff behind, making it very hard to do. Mmmm managed code, fun!
I'm not even against a new language if it can keep easy access to the low level flexibility of C/C++, but add some new constructs to make higher level things easier, because some of those higher level things in C++ are indeed confusing and dangerous and take a lot of use to master. But any new language should probably be developed and managed by a wider standards/interests committee with many parties, not just one vendor's whims unleashed upon the world - that never seems to be looked upon well by the other parties, even if the language may be the greatest thing ever you may see little buy-in because the other parties didn't feel part of the development process.