Not only syntax, a lot of the restrictions feel weird for a Java/C#/Scala programmer as well. E.g. functions needing to be declared before you can use them feels like you are coding in C again.
F# probably is a better functional-with-OO-aspects language, but C#/Scala are clearly better OO-with-functional-aspects languages and programmers currently want the latter.
I'd argue that restriction of F#'s is actually a feature. Cyclic dependencies are a real beast to reason about, and I like that F#'s lexical scoping means I need to opt-in to mutually recursive functions with `let rec`.
You're probably right that it feels unfamiliar to Java/C#/Scala programmers, but I enjoy the sense of security that F# and other restricting languages provide.
F# probably is a better functional-with-OO-aspects language, but C#/Scala are clearly better OO-with-functional-aspects languages and programmers currently want the latter.