The rebranding might make the language look sleeker and more enterprisey but it looks that they're rejecting their spirit of playfulness in order to appeal to the likes of Oracle clients and take away more Java mindshare.
I'd consider languages like JavaScript, Ruby, and Python to be playful languages by comparison.
Java 1.4 already had much more features and library offerings than Go still lacks.
Golang not well supporting supervision trees has more to do with the runtime not allowing to kill a goroutine. See http://www.jerf.org/iri/post/2930