Yawar, crediting the popularity of Rust because of syntax is misleading. Mozilla has marketing budget and people behind Rust have build very active community with weekly newsletter and know how to market. OCaml is mostly used by academia and some industry players, and marketing is not being emphasized.
ReasonML is not gaining because of syntax, it's because of huge marketing effort and easy to follow tutorials and examples and catchy websites. OCaml documentation is as plain as plain can get. Rust has a few catchy websites, tutorials and free books as well.
Viet.