OCaml might be simple and clear, but starting from Standard ML - there's a number of differences that feel like warts and needless complications for no discernable gain for the programmer.
I do think Reason fix up a few of these ancient and partially crumbled stone walls making the ocaml landscape easier to criss-cross for a new generation of programmers.
I get the reason* for Reason even though it may ostensibly be a superficial one. There was a post by someone on HN saying they started using Reason and ended up using straight Ocaml.
* My earliest memories of attempting to use Ocaml was pasting something directly from a beginner's tutorial into ocamli and getting a baffling error message. I think it had to do with use of double semicolons vs single semicolons. Yet that wasn't mentioned in the entire tutorial.
I do think Reason fix up a few of these ancient and partially crumbled stone walls making the ocaml landscape easier to criss-cross for a new generation of programmers.