I think we're cycling back towards a general preference for statically typed languages, for one thing. Additionally, a number of traditionally functional language characteristics have been finding more widespread adoption among popular languages. Putting these together, OCaml is on a short list of languages that are functional and statically typed and, uh, perhaps "intuitive" is the word I want — Haskell is not very intuitive for many people due to its lazy evaluation scheme.

In my opinion, OCaml would see even more widespread use if the documentation were improved. I find it a chore to figure out how to use OCaml well. I also would like to use third-party libraries like Jane Street's Base because they've put a lot of work into providing even more functionality in their standard library, but their documentation is absolutely atrocious (where it exists at all).

OCaml is a mature language but does not have a very supportive ecosystem. I'm hoping the renewed interest will prompt changes there.