I'm a little surprised it didn't seem that they considered a GC-less language like Rust. If your latency requirements are that strict & you're already considering a total rewrite, I would personally have been looking into a solution that would avoid GC entirely.
I agree: I personally find Rust more expressive than Go. I don't think it has any more "semantic overhead" than any other language with a highly featured type system.
To tie it back to the article a bit, Rust also seems like a relatively natural choice for a team considering switching from Haskell if their reason for switching is performance. The niche Rust fills for me personally is that it has a very robust type system (putting it in a similar camp as Haskell) with an explicit focus on fast, performant code (which Haskell does not have).
