Hm, looks like I can find examples of using kotlin with guice, and kotlin with dropwizard, but no examples of kotlin with gwizard... After recently looking at java8 and alternatives, I've tentatively come to the conclusion that I'm rather happy to use kotlin for stuff that needs to be (almost) java (eg: Android, or just mapping closely to java, eg: dropwizard?) -- and clojure for everything where java feels too constrained (but where perhaps performance isn't much of an issue). For myself, I don't see much use for scala -- it feels too complex, and in many ways less powerful than clojure. Note that I don't have any legacy java/jvm code, and so I probably just use ocaml or even standard ml where others might reach for scala.
Perhaps kotlin doesn't make much sense wrt dropwizard -- it might make more sense to just stick with java for dw, and use something different if one wants something higher level?
Anyway, some related links I've come across googling a bit:
clojure+dropwizard (example, with leiningen):
https://github.com/stevensurgnier/dropwizard-clojure
Experimental (old) repo for dropwizard+kotlin:
https://github.com/arteam/kotlin-dropwizard
Combining kotlin and guice: