[yminsky]

OCaml isn't without its warts (like any language), but I don't quite think you've nailed them.

For one, the different stdlibs are in fact highly compatible. Basic types (option, result, string, int, array, float) are all the same, so code using different stdlibs works together seamlessly most of the time.

Lwt and Async are a different story, and there is a real incompatibility problem there.

The syntax extension story is pretty clear and simple: PPX rules the roost, and the tools for building PPXs are quickly getting better and more unified. Reason is an interesting variant in the ecosystem, but its existence doesn't amount to a wart in my eyes. It's an alternative syntax that you can use interoperably with the rest of the OCaml ecosystem (and Dune makes that awfully easy.)