Hello, dear reader.
If you think that using Kotlin in Android/Whatever project is bad idea from hiring perspective in compare to Java — relax.
For example, we require experience and good understanding of RxJava (because ~90% of the app is reactive) but we don't actually pay much attention on experience with Kotlin. Yes, it'll be good if candidate has it, but it's not critical at all (our Android apps are 100% in Kotlin).
// Of course, there are a lot of factors involved in final decision.
Don't think that Kotlin will make hiring harder for you. Actually, it'll be easier to find candidates above average on the market if you'll say that your project extensively uses Kotlin!
Let's go drink after Droidcon NYC! See you on Droidcon NYC 2016!