I think kotlin is ugly hack, if you take away the superficial syntax (?) it will start showing ugly side. I think it only gotten popular because of Googles push due to Oracle Java lawsuit.
I don't think Kotlin is being pushed because of the Oracle lawsuit. Most of Oracle's complaints were at the VM and standard library level, which Kotlin doesn't help with.
Kotlin allows Google to hang out in Java 8 forever. If they want new features they can just add them at the Kotlin layer. Insulates them from OpenJDK and any changes Oracle wants to make. All great opportunities to fragment the Java ecosystem
OpenJDK was always fine for them to pull in, being GPLed. They got in trouble because they based their class library on Apache Harmony originally, and Sun pulled the TCK rug out from under Harmony.