Totally agree on 2. "Learn a language a year" they said. "Learning new languages expands your thinking" they said. What they didn't say was that once you use ADTs to model data, Maybe/Option types to avoid null, exhaustive pattern matching, etc, you want those features in all the languages you use.
I don't ask for much. I just want a GC'd Rust (one of the few modern languages that has option types in the std lib) or an F# that isn't tied to the .NET standard lib. Please?