Was expecting a Scala competitor, but found a slightly better Java with some syntax sugar. It's "nice", but not really different enough to warrant the effort of switching to another language. As a Java dev for 10+ years Scala was an eye opener on what a language could really be, Kotlin is "nice", but sadly not that interesting.
Minor pet peave is they have retained even Java's verbosity for outputting text:
Kotlin: System.out?.println("Hi") Java: System.out.println("Hi") Scala: println("Hi") Ruby: puts("Hi")
From reading the language specs it seems much more pragmatic than Scala (as does ceylon http://www.ceylon-lang.org/ or fantom http://fantom.org/).
I think if JetBrains thought that Scala was a better Java they would be using it instead of creating their own language.
I think there's definitely room for a "better Java" - most Java devs should be able to pick up Kotlin or Xtend and be more productive very quickly.
With regard to FP, I think the presence of closures is enough to do a large proportion of the things you'd want.. What do you see lacking in these?
jetbrains is an interesting company. they have managed to produce a successful product (intellij idea) despite being in competition with a hugely successful open source project (eclipse). i was thinking about this just last night, when i gave up using eclipse in despair (maven nested projects, fwiw) and decided to upgrade my idea licence to the new release - it's impressive how much better it is. so they must have some smart people; i hope this works out.
Really?