Open-sourcing it would be really cool to see. Chris Lattner last said he wasn't sure if they were going to open source it (http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-June/073698....)
C# is the only language that is both modern and spans all major mobile platforms.
Personally I consider C++14 quite modern.
I mean, look at GNUStep. Not widespread adoption.
GNUStep failure is more to do with Objective-C being such an odd language for most people.
This is only a selling point to developers that mix language with implementation, or never used a native code compiler.
The fact that it sat beneath other windows meant you had to constantly shift windows to get to it, which I found frustrating. Likely a configuration option?
It probably runs excellently on modern hardware, albeit with no GPU acceleration or anything to reduce main CPU cycles.