I wish Oracle would just offer Java editions, where they break syntactical backwards compatiblity, but retain backwards compatibility on the bytecode level. Of course, 99% of the language should stay the same with most of the syntactical changes just getting rid of the annotation mess that proper Java would be.
That is already what guest languages offer, but then there is always the caveat that their subculture only sees the JVM as a bootstrapping tool for their little ecosystem.
