Really nice work from JetBrains, this delay was annoying and I like how they have improved the IDE integration since the start
If you allow me a rant, I'm very disappointed by the state of support not in IntelliJ but in Android Studio.
It didn't seem like the Android team at Google had a lot to do to support Gradle Kotlin DSL scripts, since 95% of the work was done upstream in IntelliJ and in Gradle.
But as far as I'm concerned they did a really poor job of doing the remaining 5%.
There this very basic issue that breaks the plugins mechanism on which the IDE integration is built that was opened in August 2017 by a Gradle employee who worked on this stuff. The impact of it is huge but the fix is quite small. What happened since? Nada
Allow application of the Android Gradle plugins using Gradle's plugins block
Another low hanging fruit is that all plugins should provide documentatiion for both Groovy and Kotlin users. As you can see it, pretty much all plugin developers have done it except the Android guys
There are obvious bugs in Android Studio as well, like if you have a "settings.gradle.kts", it will happily create an additional "settings.gradle" and breaks your build.
At that point I'm not bothering to create issue on their bad issue tracker, because the real problem is that they don't understand and/or don't care about this enough to do some serious dogfooding