In day-to-day usage, the (fast) compilation speed matters much more than the (slow) implementation of new features.

I totally agree, but I'd go further and argue that slow implementation of new features is itself a desirable trait. It's one of the reasons why why I like both Go and Clojure.

Spot on. Heaven forbid it turns into a C++ (I'm not a Rust practitioner but from the outside it seems to accrete features pretty quickly as well).

The ease of grokking Go (both reading and writing) are big advantages, and facilitated by the "small" feature set of Go.

> Gophers are usually quite fast, perhaps an elderly turtle would be a better mascot?

The slow turtle wins the race against the overly eager rabbit... so I'm okay with that

The lesson of the parable of the tortoise and the hare isn't that "slow beats eager", it's a lesson against unfounded overconfidence in one's own abilities.